Seattle Mariners Top Prospects 2021: The Top 10

Prospect lists are always weird and subjective, but this was an especially weird year in which to assemble one. Not only are there new draftees to consider who haven’t yet had a chance to get their pro careers started, there are still Mariners prospects who, a year after being drafted, are yet to throw a professional pitch, as well as others who haven’t played stateside yet, thanks to the team’s tendency to slow-play college arms and international signings. This upheaval may show itself in some of our rankings priding proximity over ceiling in a way they might not in other years, or depending more heavily than we’d like on hazy pressbox-shot video from the alternate site and reading tea leaves from the box scores of the fall league.

Still, the lists must get done, so as a staff we voted, and then compiled the rankings (well. Grant compiled the rankings using Excel wizardry. Thanks Grant!). While things smooth out later down the list, in doing the Top Ten, at least, there were some players clustered together, so we noted where two prospects are neck-and-neck and where the gaps might be bigger. We’ll drop the rest of the list with writeups over the next few weeks, but here are our Top Ten Mariners prospects for 2021:

#1 and #2 (or 1A and 1B): OFs Jarred Kelenic and Julio Rodriguez

That’s weaseling, so let’s be clear: this year, Julio leapfrogged Jarred in the rankings at most outlets. We still have Kelenic as the 1A, though, and here’s our explanation:

I love the ceiling of Julio, but ultimately couldn’t ignore what Kelenic has actually done on the field. It seemed like every pitching prospect at the alternate site named him as the player they were happiest not to have to face. I think they will both be forces, twin terrors in the outfield, but Jarred got the nod from me here simply because of proximity + the fact that he truly feels like a looming threat to the AL West. (KP)

For me, it’s a matter of proximity. Kelenic has proven he can hit good pitching at AA, as well as pummell Mariners arms at the Alternate Site. Rodriguez may ultimately have the higher upside, but I think Kelenic has proven he will come up and he will make an impact, probably in May. 2021 is a big year for J-Rod to prove he can stay healthy, and work his way up into the advanced minors. (JD)

Shaq and Kobe. Sonny and Cher. Jesse and James. All dynamic duos (although the last one is from Pokémon), and all equally difficult to rank. Soon enough, Jarred and Julio will join their ranks, and soon enough, the debate on who’s better will go mainstream. I opted for Jarred since Julio has just 84 games of MiLB experience in the States — and I’m a sucker for a five-tool set — but when all’s said and done, Julio has a much higher ceiling. (GB)

#3: RHP Logan Gilbert

Sometimes prospect ranking is difficult, and sometimes it’s just “who is the next best guy in the system after Jarred Kelenic and Julio Rodriguez?” With his polished pitch mix and success all the way into the upper minors, Gilbert effortlessly slides into the third spot on our list near-unanimously. Expect to see him at T-Mobile Park sometime in 2021.

If you’re a Mariners fan but not as familiar with the systems of other teams, I encourage you to peruse some of the other prospects typically ranked around or above Gilbert. Their numbers have thinned by now, but they represent among the toolsiest, most overpowering young pitchers in the game. Nate Pearson (TOR), Matt Manning (DET), and Grayson Rodriguez (BAL) all share LoGi Bear’s size and exceed his velocities, but Gilbert’s consistent dominance may make him an upper echelon starter all the same. All four pitches play well together, with some nice tunneling and out-of-this-world extension as he drives down the mound to not only shorten the hitter’s reaction time but make his four-seam play up with deceptive ride. Kelenic is probably the surest thing in this system, but Gilbert is damn close, at least for a pitcher. He’s arguably the easiest top RHP anywhere in MiLB to look at and see a long, successful, above-average career for, and the Mariners could desperately use someone like that. (JT)

I think Logan Gilbert is one of the more slept-on pitching prospects in baseball. Everything about the player screams upside. Durability has been solid. Pitch data is solid. Upward trajectory in just about every measurable category. Big body. Big extension. The only questions I have surrounding Gilbert will be can he command his secondaries enough to vault him atop the Mariners rotation. At worst, he has the arsenal and intrinsic ability to be a really, really good #4 starter. If everything clicks, Gilbert could be a front-of-the-rotation horse that tallies 200+ innings in his prime. He’s clearly ahead of Hancock and Kirby for me, but again, I place a good deal of value in proximity bias. (JD)

If Gilbert had a couple more ticks on his fastball, he’d be right up there with Pearson, Manning, Rodriguez, and co. in rankings. As it stands, I’d rather have Gilbert’s pitch mix and mentality on the mound, and I think there’s a very good chance he’s the best out of all of them. (KP)

#4 and #5 (4A and 4B): RHPs Emerson Hancock and George Kirby

There was a gap in our rankings between the top three and these two, who both scored an average rank of 5-ish owing to a couple of 7s for Hancock (Amanda and John) as well as one for Kirby (Kate). Hancock edged Kirby by .2, but these two are as close as any on our list.

I had Noelvi Marte 4th and struggled with ordering Hancock and Kirby. Ultimately I was swayed by Hancock’s success in the crucible of the SEC, even though Kirby has so far been every bit as good as advertised and more. I think Hancock took an unfair tumble after a shaky start to his 2020 season under weird circumstances and it’s my belief that if there had been a full season, he’d have gone in the top of the draft as he was predicted to early on, so that also influenced my thinking here and ultimately caused me to bump Hancock up ahead of Raleigh. (KP)

There’s a lot to like about both Hancock and Kirby. On one hand, Hancock clearly has better secondary offerings than Kirby. On the other, I prefer Kirby’s fastball profile with his curveball playing off it. I gave Hancock the nod because he features a better changeup and a legitimate fourth offering in his curveball. Kirby has three very good pitches, but a fourth may take his game to the next level. We’ll also need to see if Kirby’s velo spike is real in-game. I put a lot of weight on Kirby’s command, and as much as I’d like to give him the nod because of it, Hancock’s *stuff* is just too good. I do worry a little about Hancock arm action, but that’s a conversation for another day. I’m sure he’ll be fine. (JD)

#6 and #7 (6A and 6B): SS Noelvi Marte and OF Taylor Trammell

Another close one. Noelvi is buoyed by two high votes (Kate and Amanda, 4 and 3, respectively) but capped by three #8 votes (Eric, Matthew, Connor). Trammell has fans in Matthew, Amanda, and John, all of whom had him at #5.

I’ll be honest: the sole reason I ranked Noelvi relatively low in the top 10 is his distance from the Majors. That’s not a knock on him! He probably has the highest ceiling out of anyone on the list not named Julio Rodríguez or Jarred Kelenic, and while there’s rumblings the club plans to be aggressive with his development, the fact remains that he has yet to play stateside other than the time he spent at the Alternate Training Site and the makeshift fall league. The earliest I’d expect him to make any real contributions in Seattle would be 2023, and even that feels like a tall order; 2023 will be Marte’s age-21 season. There is a ton to like in his game, but given how far off he is at the time of his writing, I bumped him down a couple spots in favor of players who are likely to make an impact in 2021 - especially given the strong hints dropped by Jerry Dipoto that we could see both Trammell and Cal Raleigh in Seattle at some point this summer. (CD)

I’m very hopeful that we see Taylor Trammell get a sizable amount of plate appearances in 2021 with the Mariners. After 3 trades and 426 games played in the minors, this 23-year-old outfielder and all-around excellent personality should be just about ready to launch into the majors. I hope the player dev folks are working with him to make whatever adjustments they think are appropriate for him and then he spends a couple months mashing in Tacoma before making his debut either due to injuries or another OFer has run his course. I don’t think anyone should have massive expectations for Trammell, but from what I’ve seen, he has the tools and the make-up to grow into an everyday player and with any luck make the teams who traded him look very silly. (ES)

Trammell was quite a ways down my list, closer to the no. 10 spot. He’s getting older and will have to prove he can hit sooner rather than later. Also, being on the 40-man gives the organization and Trammell less wiggle room and maneuverability. It’s a proverbial hourglass on his debut, and that’s not necessarily a good thing. The physical tools are undeniable, but a handsy swing with a flat bat-path gives me some pause. Marte oozes potential and plays a premium position up the middle… for now. He’s a budding star and could be on a similar trajectory as Julio. This will be a massive year to find out just how bright Marte’s star is going to shine. (JD)

I’m a sucker for young guys already in MLB proximity. Trammell would look far better with either another crack at AA and/or some AAA reps under his belt as he should’ve had this year, but as it is, reaching AAA at 23 with excellent speed and a reportedly strengthened arm is squarely in the excellent news category for me. Stateside players don’t typically crack the bigs even as quickly as Trammell is threatening to. I don’t know how he fits into Seattle’s big league future yet, but he’s a player I’m as excited as any to actually see get into games beyond the instructional league level. For Marte, every bit is true, and I expect to see a good deal of impact in the coming months, but until he actually starts hitting players this side of the Gulf of Mexico, I’m trying to be patient. (JT)

Actually seeing Marte in the box at T-Mobile has me bought in on him completely. I didn’t make a lot of ceiling picks this year, but I am higher on Marte than I’ve ever been from seeing his natural ability both with the stick and in the field, where I think he legitimately has a chance to stick at short with the right tutelage. I think he’ll also be a faster mover than people think thanks to his maturity, an above-average work ethic, and the ability and willingness to soak up new information like a sponge. (KP)

#8: C Cal Raleigh

Raleigh got a solid number of #7 votes (Tim, Eric, Matthew, Connor) with the high vote being #6 from Kate and the low vote #9, from Joe. 8s from Grant and John push Raleigh into this spot.

I like Raleigh a lot, but I do think his upside may be limited to a platoon bat at the big league level. I think he’ll be in the lineup as a LHH against RHP. I’m not sure the power plays as well from the right side. He’s also probably a fringe-average defensive catcher, which is fine, but again, probably plays best alongside a defense-heavy platoon like Luis Torrens. If Raleigh is a .235 hitter capable of hitting 15 to 20 home runs in a season in 350 at-bats, I’d call that a win. (JD)

I have argued this elsewhere, but I think Raleigh’s prospect hype has been unfairly dinged by factors out of his control: an injury he played through in college that depressed his pre-draft year numbers, a signing issue that resulted in a late arrival to short-season ball after he was drafted, and the shutdown in 2020 keeping him toiling in obscurity at the alternate site and in Arizona. The club hasn’t given any indication that they consider Raleigh anything other than their catcher of the future; he has been in attendance at every major development event, taken reps with the first team at spring training, and been spoken about in glowing terms for both his on-field play and leadership. Based on what I’ve seen and heard, I’m buying in on the club’s high evaluation of Raleigh, and a recent spate of successes with catching acquisition and development indicates it’s a smart buy. (KP)

Raleigh falling to #8 on my list is less of a reflection on his prospect ability and more a statement about Noelvi Marte & the impeccable command of George Kirby. I’m probably unfairly biased by his struggles in AA to finish up 2019 (.228/.296/.414, 29.6% K% rate). His contact skills are the biggest outstanding question, but if he can show progress there in 2021 while improving defensively, the M’s might have their starting catcher of the future. If not...well, that’s why they don’t pay me the big bucks. (GB)

#9 and #10 (9A and 9B): LHP Brandon Williamson and RHP Juan Then:

Photo by Abbie Parr/Getty Images

Again, there was a gap between the previous spot on the list and this one, with Williamson and Then bunched up together in people’s rankings. Several writers (Kate, Eric, Matthew, Connor) had Then right outside of the Top 10, while Joe was the highest staff member on Then, placing him at #7.

Big, big fan of Juan Then. I think he’ll contribute at a high level in whatever capacity he’s deployed. On one hand, you’ve got immediate help as a high-leverage reliever. On the other, I’m a sucker for shorter starting pitchers that exhibit strong fastball characteristics at the top of the zone. He’s got a big-spin breaking ball and a fringy changeup that could work as a starter in the bigs. He’s already a member of the 40-man roster, and that should lend well to his eventual arrival and contribution in Seattle in 2021. (JD)

I was the high one on Williamson at #8, which involved pushing Then down some. I like Then; I just think he’s more of a reliever type, whereas I think Williamson has a real chance to start given his build and physical projection (we love a 6’5” pitcher). Also I’ve seen his curveball in person and it is on its way to being a Pitching Ninja favorite, it is filthtastic. Williamson gets overlooked a lot because of all the pitching talent in the system, but I’m betting on him having a very loud 2021. (KP)