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2017 Seattle Mariners prospect rankings and overview

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A look at some of the top talents in the organization

MLB: Spring Training-San Francisco Giants at Seattle Mariners Matt Kartozian-USA TODAY Sports

Heading into 2017, the Mariners farm system is in a much better place than it was a year ago. While the raw talent hasn’t increased a ton, breakout performances from several prospects have given the organization plenty of reasons to be excited about the coming years. This probably speaks more to how dire of a situation the farm was in than it does to the overall strength of the current system–they lack a pitching prospect with a No. 3 or higher ceiling and there isn’t a third-base prospect to be seen for miles–but it’s progress.

Ahead of you, I have my personal ranking of the top-25 prospects in the Seattle Mariners system. The list is a diverse one, including several players we saw in Seattle last season and several guys we may not see until 2020. Ranking prospects is a complicated beast, full of odd reasoning and a never-ending tug-of-war between perceived ceiling and the realistic chances of them achieving that ceiling. I will be as transparent as possible in my thought process behind every selection, and I’ve included a brief Q&A at the end, full of questions I anticipate will be asked.

But enough talking. Let’s get down to business.


  1. Kyle Lewis, OF

2016: Slashed .299/.380/.530 across 135 plate appearances and 30 games with Low-A Everett in his professional debut. Had 8 doubles, 5 triples, 3 home runs, 16 walks, and 22 strikeouts during the stretch. Season came to an end after he suffered a torn ACL and meniscus during a collision at home plate.

Scouting: Best all-around talent in the system. Lewis possesses all of the traits to be a legitimate, four tool major league outfielder one day, with Adam Jones frequently cited as a comparison. The bat is Lewis’ biggest selling point. He has an advanced plate approach and patience that stems from a year’s worth of being heavily pitched around at Mercer (.395/.535/.731 his junior year). Boasts impressive power to all parts of the field and uses every bit of it. Overcomes whatever contact issues he has with selectiveness and a great eye at the plate.

Has terrific instincts and arm strength in center field, but his ability to stick at the position moving forward is shrouded with question marks due to his athleticism. Knee injury suffered midseason only increases these concerns. Projects as an above-average glove in a corner spot.

2017: Expected to return from injury around mid season, where he'll likely start out in either Class-A Clinton or High-A Modesto. We've yet to see how the Dipoto regime handles a significant knee injury, so it's hard to say how much they'll challenge Lewis when he returns.

2. Tyler O’Neill, OF

2016: Was one of the most impressive players in the Southern League, slashing .293/.374/.508 with a career-high 10.8 BB% across 575 plate appearances in Double-A Jackson. Had the fourth-highest wRC+ and eleventh-highest ISO in all of Double-A. Earned a spot in the Arizona Fall League, where he put up a 143 wRC+ (fourth-best) and hit .292/.395/.486 in 86 plate appearances.

Scouting: Tremendous raw power has the tendency to distract you from how well-rounded of a player O’Neill has become. Developed into a more complete hitter over the past year, improving his patience and approach at the plate while learning to use more of the field. Swing-and-miss aspect of his game is still present and doesn’t seem to be going away anytime soon, but improvements in other areas makes the problem look less damning than it once did. Struggles against legitimate breaking pitches limit him some as a hitter, but he punishes fastballs as well as anyone.

In the field, his surprising athleticism and range help make up for shortcomings in other areas, but there is still work to be done in that department. Expect him to develop into at least an average fielder at the next level.

2017: Should start the season out in Triple-A Tacoma, where he'll be just a short, traffic-filled drive away from Seattle. That being said, if everything goes right for the Mariners (hah), we shouldn’t see him in the big leagues until mid-season at the absolute earliest.

3. Nick Neidert, RHP

2016: Neidert made an impressive full-season debut, posting a 6.82 K/9, 1.29 BB/9, and 3.58 FIP over 90 innings as a 19-year-old in Class-A Clinton. The low innings count is due to Neidert spending time in extended spring before joining the LumberKings in late May.

Scouting: Neidert has, in my opinion, the highest ceiling of all the starting pitching prospects in the system (by a razor thin margin). Fastball runs anywhere from 90-94 with some sinking action and it’s complemented well by an advanced changeup. Command of all of his pitches is a strength and Neidert excels at creating weak contact. Ceiling comes down to the development of his curveball and slider. If he can take steps forward with either, he could emerge as a potential mid-rotation starter. If they go static on him, he’s still looking at a back of the rotation label.

2017: While common sense tells us he’ll take the next step up to High-A Modesto to start 2017, I wouldn’t be shocked to see him spend a little more time in Class-A Clinton in order to assess how his secondary stuff has improved before exposing him to the hitter-friendly California League.

4. Max Povse, RHP

2016: Povse started 2016 out in High-A, where he ran a career-best 2.86 FIP over 87.1 innings before getting the call up to Double-A. With the Mississippi Braves, Povse saw his numbers regress some, but they were still largely impressive: 6.11 K/9, 1.53 BB/9, 50% GB rate, and 3.46 FIP. Had the twelfth-best BB/9 in all of Double-A (min: 70 IP).

Scouting: Large-framed righty with a good fastball that sits in the low-90s, but will get up as high as 94. Also has an above-average changeup that he throws well in all counts and a basic curveball that is helped significantly by his size and arm slot. Deceptiveness in Povse’s delivery, along with his general size, help all of his pitches get in on the hitter much faster than expected. As a result, those 90-94 mph fastballs can behave more like 93-97.

He commands his pitches well to all parts of the zone, using the natural downward plane to generate plenty of grounders. Has sported a >50% ground ball rate in each of his last three stops. Received comps to former Mariners Chris Young and Doug Fister.

Should eventually mold into a fine back-of-the-rotation starter with a chance to be a potential No. 3 guy if the stuff continues to take steps forward.

2017: Will likely start out in Triple-A Tacoma with an outside chance at landing in the rotation sometime late in 2017. Don’t get the feeling the Mariners will be relying on him to contribute this year, but he’ll be one to keep an eye on if injuries start making their way through the pitching staff.

5. Andrew Moore, RHP

2016: Moore dominated his first full-season of pro ball, breezing through the California League (54.2 IP, 3.18 FIP, 7.74 K/9, 2.14 BB/9) and holding his own against Double-A competition. In 108.1 innings in Jackson, the second-round pick out of Oregon State ran a 3.34 FIP and 4.78 K/BB.

Scouting: Moore’s raw stuff won’t impress you at first, but plus-command and his general ability to keep hitters uncomfortable in the box help his stuff pop more. Fastball sits anywhere from 89-92 and will run up as high as 93-94 on occasion with decent tailing action. Changeup is arguably Moore’s best pitch; it has a fair amount of movement and he’s comfortable throwing it in any count to both lefties and righties. He’ll throw his curveball and slider for strikes, but he struggles to generate swings and misses with both. 12-6 curveball shows better potential, as his slider behaves like an 80 mph cutter a majority of the time.

Moore likes to work as quickly as possible on the mound and is very fluid between catching, setting, and throwing. Mechanics are interesting. Windup is fairly accelerated and plays a part in his ability to keep hitters uncomfortable.

General knowledge says that the lack of secondary offerings and inability to generate a ton of swings and misses puts his ceiling at a No. 4 starter. Moore has managed to outperform expectations so far, so I won’t be shocked if he pitches himself above that ceiling. That being said, I largely agree with the No. 4 starter assessment.

2017: Will likely get a decent look in the big league camp, with a very distant shot at grabbing that No. 5 spot in the rotation. In all likelihood, he breaks camp with Triple-A Tacoma, where he’d be a candidate for a spot start or two in Seattle at some point in 2017.

6. Mitch Haniger, OF

2016: A devout student of the game, Haniger overhauled his approach at the plate and turned in spectacular results, slashing .294/.407/.462 across 236 plate appearances in Double-A and .341/.428/.670 across 312 plate appearances in Triple-A. His 185 wRC+ in Triple-A was the highest wRC+ posted at a single level in the minor leagues last year (min: 300 plate appearances). The performance ultimately earned him a promotion to Arizona, where he managed a 0.6 WAR in 34 games with the Diamondbacks.

Scouting: Finally managed to translate his raw power to game power in 2016, bashing 30 home runs combined between Double-A, Triple-A, and MLB. Plate discipline and pitch selection improved tremendously in 2016, as well, with Haniger’s walk-rate jumping a whole 3.5% from his 2015 time in Double-A to his 2016 time in Double-A. Swing has been ironed out significantly, with a quieter load and some tweaks that have given him additional power. Power is most impressive when he’s pulling the ball, but he still boasts impressive gap power to the opposite field.

Glove is a legitimate tool for Haniger, with his athleticism and arm strength being his biggest weapons out in the field. Capable of handling center field fairly well, but will likely slot in as a corner outfielder in Seattle.

2017: Haniger is the current favorite to be the everyday right fielder for the Seattle Mariners, where he’ll get his first, long look at the major league level. Job appears to be his to lose at this point. Will likely slot in somewhere in the bottom-third of the lineup.

7. Daniel Vogelbach, 1B

2016: Made a big impression during his first year in Triple-A, slashing .318/.425/.548 with the Iowa Cubs and .240/.404/.422 with the Tacoma Rainiers. Posted a 21.2 walk-percentage with the Rainiers, which would’ve been the highest mark in all of Triple-A if it stood alone.

Scouting: Big first baseman whose value stems from his impressively polished bat. Possesses above-average power, but is willing to sacrifice it a bit for the sake of a higher on-base percentage. When he’s settled, he has a tremendous eye at the plate and is comfortable operating in deep counts. Excels at using the entirety of the field. Won’t be amazing against left-handed pitching, but can hold his own enough to where he shouldn’t need a platoon partner in the near future.

Glove is considered a bit of a liability in the field, but he’s putting in the effort to improve. Doubt he’ll ever be an amazing defender at first, but if he could get to a point where he’s competent, the Mariners should be happy.

2017: Expect Vogelbach to get plenty of playing time in Seattle this year, even if they decide to break camp without him. Vogelbach has proven all he can against Triple-A pitching at this point and the Mariners seem to be very high on him.

8. Drew Jackson, SS

2016: Jackson was aggressively pushed up to High-A ball to start 2016, where things didn’t go exactly as planned. The Stanford product got out to a slow start and never recovered, finishing the year with a .258/.332/.345 slash line and an 88 wRC+. He was then oddly sent out to the Arizona Fall League, where the struggles only grew worse (.149/.231/.170).

Scouting: Glove-first shortstop with arguably the best arm in the system. Has good range at shortstop thanks to above-average athleticism and projects to be a MLB-quality shortstop in the near future if he can clean up routine mistakes.

Ceiling will come down to his bat. Possesses a quick line-drive stroke, but lacks much power and was eaten alive by California League and Arizona Fall League pitching in 2016. Potential to be an average hitter in the future is there, but could be looking at a career as a bench utility player if he’s unable to take a step forward at the plate.

2017: Expect him to repeat High-A in 2017, where bigger things will be expected of him.

9. Brayan Hernandez, OF

2016: The 19-year-old was beating up on Dominican Summer League competition for 31 games before he was brought over to the states to compete in the Arizona Fall League. In 33 games with the AZL Mariners, Hernandez hit .285/.324/.400 with 8 doubles, 2 triples, and a home run during the championship run.

Scouting: Teenage, toolsy centerfielder with tremendous athleticism and some intriguing power potential. The switch-hitter can line the ball all over the ballpark and could develop legitimate gap power as he grows into his 6’2 frame. Looks much better from the left side at this point, but tools are there for him to stick as a switch-hitter.

Defensive tools are a safer bet at this point. Hernandez is a blur in the field and he possesses impressive arm strength that should only get better moving forward. Has all the tools necessary to be a MLB-quality center fielder.

2017: We could finally see Hernandez make his first appearance outside of the poorly-covered rookie leagues in 2017. If it does happen, expect it to come in June when the Everett AquaSox’s season gets underway.

10. Joe Rizzo, 3B

2016: Rizzo made his pro debut with the AZL Mariners, slashing .291/.355/.392 across 169 plate appearances. He finished with 7 doubles, 1 triple, 2 home runs, 17 walks, and 36 strikeouts.

Scouting: Rizzo is a teenage, bat-first prospect who is still a long way away from Seattle. He has an advanced approach at the plate and manages to frequently square up pitches to all parts of the field. Raw power is there, it’s just a matter of when he’ll start translating it to game power. Swing actually reminds me of Dan Vogelbach quite a bit.

Defense is a big question mark for Rizzo. He has above-average arm strength, but there’s doubt he’ll be able to stick a third base moving forward due to his lack of a general feel for the position. I anticipate him eventually moving to first, but the Mariners will absolutely do everything they can to help him excel elsewhere.

2017: I anticipate him staying in extended spring until Everett’s season starts up. They might even have him repeat the AZL, but the former seems more likely.

11. Dan Altavilla, RHP

2016: Made the long-awaited switch to the bullpen, where he became an immediate force for the Jackson Generals. In 56.2 innings in Double-A, Altavilla ran a 10.32 K/9, 3.49 BB/9, and a 3.04 FIP, garnering praise from everyone in the organization. He eventually received a call-up straight to Seattle, where he ran a 2.01 FIP and 3.23 xFIP over 12.1 IP (10 strikeouts, 1 walk).

Scouting: While Edwin Diaz was out stealing the show, Altavilla was quietly developing into one of the best arms in the system. His electric fastball sits in the mid-90s and gets up as high as 99. He’ll also mix in a power slider that sits in the upper-80s and can generate lots of swings and misses when he’s commanding it well.

Control can be an issue at times with Altavilla and his ceiling as a reliever will ultimately come down to how consistent he can be at the next level. All the tools are there for him to be an effective power relievers for years to come.

2017: Will compete against a very crowded field for a spot in the Mariners bullpen. At this point, I’d say one of the spots is his to lose.

12. Guillermo Heredia, OF

2016: What appeared to be an afterthought signing in the early stages of spring training last season turned out to be a big one for the Mariners. The 26-year-old Heredia, who was away from the game for some time after defecting from Cuba, went to Double-A Jackson and slashed .293/.405/.376 across 260 plate appearances. He was called up to Triple-A in late June and proceeded to perform well for Tacoma, as well. A month later, he was brought up to Seattle, where he managed a 92 wRC+ and a 0.4 fWAR in 45 games with the Mariners.

Scouting: Heredia’s biggest selling point was always his defense. He played primarily in the corners for the Mariners, but he’s capable of playing all three outfield spots and playing them well. Spectacular athleticism and a strong throwing arm serve him well in all three spots.

Bat was the biggest question mark for Heredia and he silenced some doubts significantly in 2016. Has an advanced approach at the plate and rarely chases pitches out of the zone. Comfortable operating in deep counts and his pitch recognition was better than most I saw in the system last year. His biggest weakness right now is his inability to hit the ball hard. Pitchers may start challenging him more if he doesn’t add a little more pop to his game.

2017: Competing against Ben Gamel for the fourth-outfielder spot on the roster. Have to imagine that he’s the favorite right now, but the Mariners could opt to send him down to Triple-A in order to get consistent playing time.

13. D.J. Peterson, 1B

2016: Rebound season with the Jackson Generals. Peterson slashed .271/.340/.466 (133 wRC+) with the Generals before receiving a promotion to Triple-A Tacoma. With the Rainiers, he hit .253/.307/.438 before a hand injury ended his season.

Scouting: Overhauled mechanics included a quieter stance and simpler load that helped him keep his front half from flying open. Focused on using more of the field and being more selective at the plate, leading to a 53-point increase in his wRC+ from 2015 to 2016. Has spectacular raw power and started to translate it to game power more often, finishing the year with 19 home runs and 28 doubles. There is still a lot of swing-and-miss in his game and he’s very prone to chasing breaking pitches away, but last year was a very positive step forward for him.

Despite still getting playing time at third base and the brief plan to get him outfield experience last season, Peterson will be a first baseman and DH moving forward. He has the throwing arm for both third base and a corner outfield position, but he doesn’t move well enough to positively contribute at either.

This will be a big make or break year for Peterson. A subpar year could drop him off top prospect lists permanently, while a big year could help Peterson re-establish himself as a potential everyday first baseman in the future. As it currently stands, he projects as a bench or platoon bat.

2017: Expect Peterson to start out in Triple-A, where he’ll get his first, long look against Pacific Coast League competition. Won’t be surprised if we see him in the majors at some point this year, be it with the Mariners or another organization.

14. Christopher Torres, SS

2016: Made his stateside debut, slashing .257/.337/.359 with 9 doubles, 4 triples, and 12 stolen bases over 44 games with the AZL Mariners. Spent all of his time at shortstop.

Scouting: Teenage middle infielder who, while being a long, long way from MLB-ready, shows significant potential. Has all the tools to stick at shortstop moving forward, with plus athleticism, arm strength, and range. Will need to clean up his game some, but that’s not exactly unheard of for a 19-year-old. Second base would be the likely fallback plan should he not develop as expected.

Switch-hitter at the plate. Swing is a lot smoother from the left side and he ran a pretty heavy split last year. Torres has a bit of power potential which could become more apparent as he gets older and stronger. May not develop legitimate home run power, but should absolutely have some intriguing gap pop. Plate approach is advanced for someone his age.

2017: Like Hernandez, I expect Torres to make his 2017 debut when Everett’s season gets underway. It will be nice to get a long look at him and Hernandez in a league/level that gets a little more video coverage than the rookie leagues.

15. Rob Whalen, RHP

2016: Played across three levels (AA, AAA, MLB) in 2016, totaling 144.2 innings. Posted a 3.19 FIP across 101.1 innings in Double-A before getting bumped up to Triple-A. In Triple-A, Whalen ran a 2.53 FIP with an 8.68 K/9. Made a brief cameo with the Braves, striking out 25 over 24.2 innings and finishing with a 4.77 xFIP and 5.05 FIP against major league competition. Whalen’s 8.35 K/9 mark in Double-A was the fifteenth-highest mark amongst all Double-A pitchers (min: 100 IP).

Scouting: Whalen’s arsenal consists of several pitches that range from average to below-average. Fastball sits 88-90 with decent sink action. Against righties, he’ll heavily mix in an MLB-quality slider that he’ll pound the lower left edge of the zone with. Opts for a fastball-heavy approach against lefties with the occasional mid-70s curveball. Changeup sits in the low-80s and has the potential to be a league average pitch.

While Whalen lacks a dominant arsenal and stellar command, he manages to get by on sheer baseball IQ, effectively mixing pitches and location and keeping hitters guessing. Will struggle mightily when he’s over the plate with his offerings, but tends to miss off the plate more often than not. Ceiling is that of a back of a rotation starter and I can’t imagine it ever getting any higher.

2017: Should start out the year in Triple-A Tacoma’s rotation. Expect to see him in Seattle at some time when injuries start popping up. Will be a legitimate candidate for a rotation spot starting next year.

16. Dillon Overton, LHP

2016: Performed well in Triple-A, running a 3.46 FIP over 125.2 innings, the fifth-lowest mark in Triple-A (min: 125 IP). Was called up to Oakland at various points throughout the season and slumped through a brutal stretch. In 24.1 innings with the Athletics, he posted a -0.9 fWAR and 9.15 FIP

Scouting: Tall, lanky lefty who runs a basic fastball-changeup-curveball arsenal. After tommy john surgery, the fastball velocity dipped down a bit and he now sits in the 87-89 range. When the command is on, Overton loves to pound the corners with his fastball and will generate a lot of lazy fly balls. Other offerings are a fringe curveball and a changeup that has the potential to be above-average. He began adding a cutter to the mix in 2016 and it’s a pitch he may NEED to develop if he is going to make it as a major league starter. The lack of velocity and movement on his four-seam makes him vulnerable to hard contact when he’s even the slightest bit over the plate with his offerings.

He lacks deception with his delivery and may need to tinker with his mechanics to become more effective. Once again, developing a cutter that he's comfortable with throwing a decent percentage of the time would go a long way for him.

2017: Expect him to start the year in Triple-A and be third or fourth in line to spot start/fill-in for Seattle.

17. Ben Gamel, OF

2016: Slashed .308/.365/.420 in Triple-A Scranton/Wilkes Barre with a brief appearance in New York (10 whole plate appearances) mixed in. Was traded to the Mariners midseason, where he got a legitimate chance to play at the MLB level. Posted a 59 wRC+ and -0.2 fWAR in 27 games (47 plate appearances) with the Mariners.

Scouting: Gamel tinkered with his swing some in 2015, adding a leg kick and focusing more on lining the ball to all fields instead of hitting for power. The adjustments helped him be quicker to the ball, and thus make contact more frequently and give him a better shot at being a major league hitter, as his power is hardly a reliably consistent tool.

Defense plays best in a corner, but he’s a player you can live with in center field in short stints. Solid jumps and quickness help make up for his lack of prototypical center field speed. Throwing arm won’t stand out much, but it’s good enough to hold up at all three spots.

At this point he projects to be a fourth outfielder. The bat isn’t good enough for an everyday corner spot and the glove isn’t good enough for a center field role, where the bat projects best.

2017: Will compete with Guillermo Heredia for the fourth outfielder position on the 25-man. Should get plenty of playing time in Seattle throughout the year regardless of what happens in Spring Training.

18. Thyago Vieira, RHP

2016: Spent the whole year in High-A Bakersfield, where he ran a 2.97 FIP and 10.76 K/9 over 44.1 IP. 3.65 BB/9 was the lowest walk-rate he’s posted since his time in rookie ball in 2012. Earned a spot in the Arizona Fall League, where he enjoyed a breakout performance (1.71 FIP, 7.00 K/BB in 5.1 IP). The stint was brief, but it put him on the map in a big way.

Scouting: One of the hardest throwers in baseball. Vieira’s fastball sits in the high-90s and has gotten all the way up to 103 mph at times. Power slider sits 77-79, but can bump up to the low-80s. Command of both pitches took a big step forward last year, but it’s something he’ll still struggle with, specifically in terms of working ahead of hitters. Fastball has added some sink to it, but it’s a fairly straight offering.

There’s a controlled violence to his mechanics. Has gotten a lot better at repeating his wild delivery, which has helped tremendously with the command issues.

2017: Should start out in Double-A, where he’ll get a chance to showcase his electric stuff in the Texas League. Could go the Diaz route and get called up straight to Seattle if he performs well in Arkansas.

19. Bryson Brigman, UTIL

2016: Slashed .260/.369/.291 for the Everett AquaSox over 318 plate appearances. Had six doubles and a triple. Split his time between shortstop (51 games) and second base (15 games).

Scouting: Has all the makings of a future super utility type player. Drafted as a shortstop out of San Diego, but skills aren't considered good enough to stick as an everyday player at the position moving forward. Has the potential to be a plus-defender at second base and should pick up outfield experience as he moves through the organization.

Speed and contact are his biggest assets at the plate. Frequently puts the ball in play and has the ability to wreak havoc on the base paths. Will need to add muscle, had one of the lowest slugging-percentages in the Northwest League amongst regular players (min: 200 PA).

2017: Should start out at Class-A Clinton, where he may start the process of becoming a utility player, especially if fellow shortstop Donnie Walton joins him at the level.

20. Braden Bishop, OF

2016: Slashed .290/.363/.331 in Class-A Clinton before getting the call up to High-A Bakersfield. With the Blaze, Bishop hit .247/.300/.319 over 184 plate appearances. Dealt with injury issues at times. Played all three outfield positions, but spent most of his time in center field.

Scouting: Glove-first outfielder who has some of the best wheels and defense in the system. Plays a spectacular center field and there’s little doubt he’ll be capable of covering a big league outfield in the future.

Biggest question mark for Bishop has always been his bat. Had a breakout junior year at Washington that helped him get selected in the third round of the 2015 MLB Draft and the bat is yet to crater against minor league pitching. Would like to see the walk-rate increase and the power numbers sneak up a tiny bit, but a defense-first center fielder could do a lot worse. Bishop manages to put the ball in play frequently and as long as the bat doesn’t fall apart, he should reach the majors in some capacity eventually.

2017: Will likely get a full-season’s worth of playing time in High-A Modesto. Would need to really explode on offense to receive an aggressive promotion to Double-A.

21. Greifer Andrade, MIF

2016: Lit up the Arizona Rookie League, slashing .341/.396/.549 with 2 doubles, 3 triples, and 3 home runs over 91 plate appearances (161 wRC+). Had a very brief cameo with the Everett AquaSox. Played 2B, 3B, and SS.

Scouting: 20-year-old middle infielder who flashed serious potential at the plate in the Arizona Rookie League last season. Good contact skills and manages to spray line drives all over the field. Raw power should start becoming more evident as he matures and adds muscle.

Seems to be settling in at second base. Glove and athleticism at the position are decent, but he still has a lot of work to do moving forward at the position.

2017: Could shoot up the boards if he keeps hitting in full-season ball. Guessing we won’t see him until short-season ball gets underway, but there’s a chance they put him in Class-A Clinton depending on how he looks at Spring Training.

22. Tony Zych, RHP

2016: Managed a 2.49 FIP and 3.71 xFIP over 13.2 innings with the Mariners. Ran a 13.83 K/9, which is the tenth-best mark in all of baseball if you’re willing to drop the innings minimum requirement all the way down to 10 innings. Rotator cuff tendinitis derailed what many predicted would be a breakout season for Zych.

Scouting: I hesitated to put Zych on this list because injuries are the only reason he didn’t meet the service time limits for rookies, but here we are. He still has some of the best pure stuff amongst Mariners relievers, featuring a fastball that sits mid-90s and a power slider so filthy that it was christened ‘Satan’s Frisbee’.

Command and health issues will always be the concern with Zych. He turned in spectacular walk-rates in 2015, but things went haywire again in 2016 (6.59 BB/9).

2017: Will start out the year rehabbing his shoulder, but is expected to be back sometime around the end of Spring Training. If he remains healthy, expect him to play a big role in the Mariners bullpen this year.

23. Brandon Miller, RHP

2016: Posted a 3.24 FIP and a 7.29 K/BB over 56.1 innings with the Everett AquaSox. Named to the Northwest League All-Star team.

Scouting: Miller’s arsenal features a 89-91 fastball, a 77-79 slider with good late break, and a fringe changeup and curveball. While none of his pitches are considered spectacular, he makes up for it with stellar command of all of his offerings. He’ll throw his fastball consistently to all parts of the zone and the slider will generate swings-and-misses.

Has tremendous makeup and will need to refine his secondary stuff moving forward. Slider shows the most potential, but the development of a changeup could go a long way for him. Would like to see him build up stamina in the future and manage to be more effective deeper in games.

2017: Will start out at either High-A Modesto or Class-A Clinton. Gut says Clinton at this point. Has the potential to move somewhat quickly through the multiple levels of Single-A ball.

24. Pablo Lopez, RHP

2016: Full-season debut went well for Lopez, who posted a 3.19 FIP and 6.22 K/BB over 84.1 innings with Class-A Clinton. 0.96 BB/9 was the fifth-lowest mark in the Midwest League (min: 50 IP).

Scouting: Raw, right-handed pitcher who put together a terrific season. Despite his large frame, Lopez values command and pitching to contact over velocity. Arsenal is fairly fastball-changeup heavy, but he’s still young and has time to develop the secondary stuff.

2017: Similar to Neidert, I expect him to move on to High-A Modesto, but would understand if the Mariners want to give him more time in Clinton to refine his stuff before the hitter-friendly California League.

25. James Pazos, LHP

2016: Pitched 31 total innings in the minors, posting a >13.50 K/9 and <3.00 FIP at both levels. Had a 3.1 inning stint with the Yankees, recording three strikeouts and a walk while surrendering 5 earned runs.

Scouting: Arsenal consists of a mid-90s fastball with movement and a 79-81 mph slider that will carve up lefties. Can pitch effectively to righties and surrendered just 2 hits to lefties in the minors last season. While the pure stuff is remarkable, command is a major concern with Pazos, as he struggles to consistently locate both of his pitches.

Looks borderline unhittable when he’s locked in, but those moments are few and far between. Had several chances with the Yankees to get the problems ironed out, but things never quite clicked.

Modeled his new mechanics after Andrew Miller, quieting the leg kick and having much more of a direct approach to the plate. Walk-rate improved tremendously after the change, as he posted a 3.79 BB/9 from May to the end of the season and walked just one batter over his final nine innings in the minors.

2017: Will compete for a spot in the Mariners bullpen, but the most realistic scenario consists of him going to Tacoma to work with pitching coach Lance Painter, who just last year managed to solve the pitching woes of a large, fireballing lefty named James.


Positional Breakdown

Starting Pitchers: 7, Relief Pitchers: 4, Catchers: 0, First Basemen: 2, Second Baseman: 1, Third Baseman: 1, Shortstop: 3, Outfielders: 7


Guys who just missed the cut (no particular order)

Nick Wells: 6’5, 20-year-old lefty who spent most of 2016 with Class-A Clinton. Biggest weapon on the mound is an advanced curveball, but struggles with command and other offerings. He’s all raw stuff right now and could be a decent prospect if he manages to put all of his intriguing tools together. Ran a 4.86 FIP and 1.58 K/BB in 84.1 innings in Clinton.

Nick Zammarelli: 22-year-old INF. Ran a 141 wRC+ with 18 doubles, a triple, and 5 home runs in Low-A Everett in 2016. Would like to see more contact from him, but there’s intriguing power potential there and he uses the whole field well. Not sure if he sticks at third base in the future, with a corner outfield spot and first base being the most likely alternatives.

Donnie Walton: 22-year-old middle infielder who slashed .281/.361/.421 with Everett last year. Switch-hitter whose swing is a lot better from the left side. Doesn’t have any standout tools, but doesn’t have many weaknesses, either. Tremendous makeup. A decent bet to reach the big leagues one day in a utility role.

Tyler Marlette: 24-year-old catcher who finally started piecing his swing back together after a subpar 2015. Slashed .273/.335/.472 with High-A Bakersfield and .300/.333/.400 with Double-A Jackson. Very much a bat-first prospect, but the glove has improved nicely over the past couple seasons. If the bat holds up moving forward, he could make it as a backup catcher in the big leagues fairly soon.

Emilio Pagan: 22-year-old righty with a mid-90s fastball and a wipeout slider. Has generated impressive strikeout-rates wherever he’s pitched. Appeared to be on the fast track to Seattle, but command ran into a wall in Tacoma and never recovered. Pitched in the Arizona Fall League, where he ran a 6.55 BB/9 over 11 innings. Has potential to be a middle inning reliever if he gets his control back on track and starts throwing strikes again. Pure stuff is impressive.

Paul Fry: 24-year-old bullpen candidate. Managed a 10.64 K/9 and 3.51 FIP across 55 innings in Triple-A Tacoma last season. Above-average fastball that hovers around 90 mph and a hard, biting slider that will generate a lot of whiffs. Changeup isn’t at the same level as either of those offerings, but it has the potential to be an average pitch. Control tumbled a bit in 2016, resulting in a career-high 5.07 BB/9, but he has the potential to be an effective, middle inning reliever for the Mariners very soon.

Tyler Smith: 25-year-old who hit well at every level before his first taste of Triple-A ball in 2016. Talented, versatile defender capable of handling shortstop, second base, and third base, though he’s best at second. Decent contact skills, but a lack of power gave Triple-A pitchers no reason to fear pounding the strike zone, leading to a plummeting walk-rate (4.8 BB%). Will compete with Shawn O’Malley and Taylor Motter for the utility bench job this spring.


Anticipated FAQs

  • Where is Boog Powell?

I have always been high on Powell. I was somewhat relieved when the A’s traded him out of the division and I was pretty pumped when the Mariners brought him in last year. That being said, he was having a fairly down year in Tacoma last year before he was hit with a second PEDs-related suspension. If he bounces back in 2017, he could shoot right back up this list when I revisit it around the All-Star Break. I believe Kyle Glaser of Baseball America said it best during a prospect chat back in December. A commenter asked him if Powell was still considered a prospect in the organization and Glaser stated that the whole point of a prospect is to be someone who can help the major league team in the future and how that is rendered impossible if you can’t keep yourself on the field.

  • WHERE IN THE HELL IS ERIC FILIA AND NICK ZAMMARELLI?

I’M SORRY I LOVE ERIC FILIA AND NICK ZAMMARELLI AS MUCH AS YOU, I SWEAR. Look, one thing I really try to do here with my coverage is hold back on getting you psyched about guys who may not turn into much down the road. Filia (597th overall) and Zammarelli (237th overall) are both later draft picks who are yet to play above the Northwest League. Offensively, they both outperformed Brigman, who did make the list, but Brigman has far better defensive tools, is a full-year younger than Zammarelli (three years younger than Filia), and is considered to be a much better hitter than he was during his stint in Everett. I am intrigued by both and am prepared to add them both to this list should they perform well in Class-A Clinton/High-A Modesto.

  • Why is (insert middle-of-the-pack prospect) higher than (insert middle-of-the-pack prospect)?

Honestly, once you get past Christopher Torres, the prospects turn into a game of “Spot the differences in these two pictures of clear, blue skies”. Rankings 15-25 all have one or two neat tools, but shortcomings or general rawness in other areas hold them back. You can arrange them in several different orders that will seem justifiable.

  • What factors weighed the heaviest in your rankings?

I try to find a happy balance between potential ceiling, performance, and distance from contributing to a major league team, with the former two having the most weight. AZL guys like Hernandez, Torres, and Andrade are all exciting and they could all shoot up this list in the future as they move up levels in the organization, but their distance from being major league ready keeps them down. Drew Jackson struggled mightily in 2016, but it’s hard to drop a guy who has all the tools of a starting MLB shortstop too far down the list.

  • Why is Kyle Lewis higher than Tyler O’Neill?

I can’t emphasize enough how little of space separates these two for me. This isn’t a unique take; a quick glance at just about any top-100 list will show the two nearly side-by-side. I like Lewis’ ceiling a little more than O’Neill’s, and Lewis’ general lateness to full-time baseball suggests he has still has a lot of room to improve, which is kinda scary for everyone else.

  • Your rankings are bad and I hate you.

That’s not a question, but okay that’s fair.

  • My question is not listed above. What do I do?

Leave it in the comments! I’ll do my best to answer any questions people have regarding who is on the list, who is off it, or anything else prospect-related. Or, hell, give me your own top-ten. If there’s one thing baseball fans never agree on, it is prospects. (Civilly) Argue away!