We’ve headed into the top 20 for our list of the Seattle Mariners top prospects at the outset of 2023! This batch includes many of the highest upside hitters in the system, most of whom are merely wanting for playing time to showcase where they might leap to next. To catch up on the first installment (Nos. 45-31) as well as our grading rubric, click here. To read about group 30-21, click here.

...continuing from Tier 4

20. Michael Morales, RHP

Age: 20 / B/T: R/R / Draft: 2021 (3rd) / Final level in 2022: Low-A / MLB ETA: 2026
2022 stat of note: No one is allowed to look at Michael Morales’s stats

It’s me, hi, I’m the Michael Morales fan club, it’s me. As someone who watched most of his starts with Modesto last year, I promise you Morales is a better pitcher than what his line shows, as he suffered more than his fair share of defensive meltdowns behind him and relievers who were about as much relief as putting hot sauce on a sunburn. Nothing Morales works with is especially loud, with the curve maybe being his best pitch from both a stuff and whiff-getting perspective. But he is Literally Twenty Years Old, and the Mariners challenged him with an aggressive full-season assignment after he pitched just one competitive inning in his draft year, and to his credit, Morales never seemed to let the various bad breaks get to him on the mound.

FV: 45 - With poor stats and stuff that doesn’t make scouts’ eyes go all awoogah-homina-homina, Morales will take a hit in prospect rankings this year, but again, Don’t Make Me Tap the Sign (the sign says he is literally twenty years old). -KP

19. Zach DeLoach, OF

Age: 24 / B/T: L/R / Draft: 2020 (2nd) / Final level in 2022: Double-A / MLB ETA: 2024
2022 stat of note: Walked 14.2% of the time in 499 plate appearances at AA-Arkansas

Zach DeLoach will never be on the cover of GQ. He will never have a 20/20 season. He will never compete in the Home Run Derby. If it wasn’t clear already, Zach DeLoach is not Julio Rodríguez. However, he is a fourth outfielder! Teams need those! DeLoach is defined by his ability to do basically everything on the baseball field at an acceptable level. Don’t bank on him winning you many games, but damn it he probably won’t lose you many either. DeLoach has steadily performed at every step of the minor leagues, but he has not dominated quite to the level that might’ve been hoped from a somewhat surprising 43rd-overall selection. His numbers won’t make anyone’s jaw hit the floor, but I would be remiss if I were to imply they were inherently bad. Off to a hot start in 2023 and now at Tacoma, perhaps Zach can break his AAAA player comp and tap into some additional tools that got him drafted in the first 50 picks of his draft class. Interestingly, the club has been working him at CF again in Tacoma this spring after a primarily (and previously more fitting) corner outfield role.

FV: 45 - Zach DeLoach is exactly what you think he is. He can easily fill in for the big league team right now if need be. Low-variance prospect with a ceiling that will be defined by his bat. Those at top of the M’s FO still love his swing. -ME

18. Tyler Locklear, 1B/3B

Age: 22 / B/T: R/R / Draft: 2022 (2nd) / Final level in 2022: Low-A / MLB ETA: 2026
2022 stat of note: Leads M’s 2022 draftees in professional home runs (9).

Tyler Locklear: Professional hitter has a real nice ring to it. The Mariners second round pick from last year’s draft, the corner infielder was long considered a premier bat throughout his college years at Jerry Dipoto’s alma mater VCU. Since arriving in the Mariners organization, Locklear has done nothing but rake. With an OPS of .870 in his first year, the first baseman already finds himself in A+ ball Everett. Locklear is keen to take his walks and avoids strikeouts at a decent clip considering his prodigious power. Unfortunately, Locklear is almost certainly a first baseman in the big leagues. While he is not un-athletic by any means and sports an excellent arm, he could be affectionately referred to as Ty France-esque, in ways both positive and limiting. The Mariners drafted Locklear for the bat, which places enormous pressure on him as a righty-hitting 1B. Locklear’s strength helps him muscle the ball with authority, but he has stellar bat speed as well, which helps him stay on pitches long enough to stay alive when fooled.

FV: 45 - Locklear hits the ball incredibly hard and maintains an excellent approach at the plate. His lack of defensive versatility limits his value, however, necessitating the hit/power combination to continue to grow as he progresses through the upper minors. -ME

17. Walter Ford, RHP

Age: 18 / B/T: R/R / Draft: 2022 (2nd) / Final level in 2022: N/A / MLB ETA: 2028
2022 stat of note: Being literally 17 years old

For being freshly out of high school and without any organized professional ball under his belt, this is pretty high, honestly. The supplemental second-round pick for the Mariners has a few distinguishing traits: a fastball that was already ticking up towards 96 as a 17-year-old, a banger breaking ball, and a deep, burning desire to brand and market himself - the “Vanilla Missile” (it is unclear if he gave himself this nickname) is quite active on Twitter, a social media site he could probably afford to take a step back from. But none of that overshadows what is a truly electric arm, advanced feel for the zone and a fiercely competitive approach on the mound. He was one of the top prep arms in the draft, even after reclassifying from the 2023 to the 2022 draft class, a year earlier than expected. I am incredibly excited to see what he brings to the ACL this season.

FV: 45 - This is a toughie because the variance is so high and he’s so young, giving an FV feels pretty pointless at this point. He could be literally anything from a top-of-the-rotation Dude to an org Guy. He slots in this high based on the upside and the belief the organization has placed in him already. -NV

16. Alberto Rodríguez, OF

Age: 22 / B/T: L/L / Signed: 2018 / Final level in 2022: High-A / MLB ETA: 2025
2022 stat of note: 26.2 K%

My man just could not get it going last year. In the past, Berto had gotten off to a slow start in the colder months before going nuclear in the summer. 2022, though, saw him go more lukewarm as July rolled around - if you tasted his season as you were heating it up on the stove like leftovers, you’d probably say “Mmmm, a few more minutes. I mean it’s warm, it’s just not hot yet.” A pretty mediocre season for the promising Cotuisano is one he hopes to wipe from his memory. He put in a ton of work this offseason on his swing and his conditioning, a topic that he expanded on in a delightful interview with Kate. If he can continue to refine his funky swing path and get the hands quieter while still finding the barrel, he should move to AA sometime this season. He’s gotten back to making better swing decisions as he did in his standout 2021 campaign so far this swing.

FV: 45 - This is sadly lower than he has been ranked in years past - he currently projects as a fourth outfielder right now, if things go well. I hope to see him change this path this year with a monster season. -NV

Tier 3

15. Michael Arroyo, INF

Age: 18 / B/T: R/R / Signed: 2022 / Final level in 2022: DSL / MLB ETA: 2028
2022 stat of note: 16.6 K% with a 13.6 BB%

Michael Arroyo needs a bigger fan club. I’m not sure of the exact member count to date, but I do know if Michael Arroyo has no fans, I have perished. Signed out of Colombia in 2022, the young infielder has a very advanced hit tool that could easily develop alongside average power. He has a discerning eye, avoids strikeouts, takes his walks, and displays good athleticism on the base paths and on the dirt. I cannot stress this enough: There is a more than legitimate shot Arroyo is an above average second baseman with a plus hit tool and average power or better. Granted, Arroyo is quite literally 18 years old, and the DSL is laden with pitchers throwing in the mid-to-upper 80s and with little in the way of control or quality offspeed. A lot of things can happen between being a teenager and making the big leagues. That said, the advanced contact ability, athleticism, and growing power stroke make Arroyo one of my favorite prospects at any level in the system. He should see the ACL this year and could be among the wave of later season call-ups to Modesto if he performs well.

FV: 50 - I’m staking my claim to Arroyo with this grade, but I tend to favor higher upside prospects for the impact potential they can have on a franchise. With as advanced as the hit tool is, I struggle to see a world where he fizzles out entirely. Michael Arroyo fan club, unite! -ME

14. Felnin Celesten, SS

Age: 17 / B/T: S/R / Signed: 2023 / Final level in 2022: N/A / MLB ETA: 2028
2022 stat of note: Has a chance to be the first Mariners big leaguer to be born after Félix Hernández’s MLB debut.

By all accounts I’ve seen from people well connected to the Mariners and nationally covering international amateurs, Felnin Celesten is a special, special prospect. Signed out of the Dominican Republic in the 2023 international class, Celesten is considered one of, if not the best shortstop prospect out of the Dominican in the last decade. The switch-hitting shortstop shows a polished hit tool and loud power from both sides. He has filled out considerably and will be a strong, physical player that will assuredly stay at shortstop. He’s the kind of prospect that doesn’t just grow on trees. Loud, loud, tools across the board with the floor of an excellent fielding shortstop. I would hate to put unwarranted expectations on the exceptionally young man who is still just 17, but the sky is truly the limit. Obviously a lot has to happen for him to be a big leaguer, but the kind of praise Celesten receives does not get thrown around haphazardly.

(Ed.’s note: Since I suspect it may be a point of query, our ranking is more measured, as it often is for players who’ve yet to set foot stateside. It’s a concession to the limitations of what we can analyze from here, and an acknowledgement that there is Wander Franco and there is Robert Puason, there is Marco Luciano and there is Kevin Maitan. Expect Celesten to rocket up as we see him get into games. -JT)

FV: 50 - The tools are far too loud to warrant anything below this, but he’s untested to grade anything above this. This grade will be higher as soon as he gets some DSL time under his belt and we can start to appraise who the M’s have on their hands. -ME

13. Jonatan Clase, OF

Age: 21 / B/T: S/R / Signed: 2018 / Final level in 2022: Low-A / MLB ETA: 2025
2022 stat of note: 55 stolen bases in 65 attempts.

Jonatan Clase is someone you can’t possibly root against. Signed out of the capital of the Dominican Republic, Clase was not afforded the luxury of a hefty signing bonus or granted opportunities to train with the big leaguers right away. The small-statured Clase worked his tail off and transformed his body physically. Now a strong, compact center fielder with elite speed and a lefty swing with some juice, Clase could prove to be a menacing table setter at the next level. His routes have improved defensively, and he has the athleticism and pure speed to cover far more ground - and compensate for mistakes - in a way few players can match.

The speed has always been definitional to Clase’s profile places his floor well above most players, and thus he is likely a center fielder with plus defense and pinch-running capabilities. The improvements to his muscularity and pitch recognition, however, have him off to a torrid start in 2023 that could render this ranking quaint.

FV: 50 - If a player has a tool that is truly elite, rarely do they find themselves without a place on a big league roster. To what extent I don’t yet know, but there is assuredly a place on a big league roster in Jonatan Clase’s future should he continue the path he’s on. Clase’s floor is among the highest you’ll find for a player his age, and the ceiling continues to be vaulted. -ME

12. Isaiah Campbell, RHP

Age: 25 / B/T: R/R / Drafted: 2019 (2nd) / Final level in 2022: Double-A / MLB ETA: 2023
2022 stat of note: 26.3 K-BB%

What a funny career he’s had so far. After being drafted in 2019 as a powerful starter who notably had a lot of miles on his arm, injuries set the big-framed Campbell back for two years. The former Razorback started 2022 in A+, before another minor injury wiped out all of May for him. When he returned, it was out of the pen, and it was notable - my man threw 12 straight innings of no-run ball, and after giving up just one run in 15 outings, it was off to AA for the Lusitano. His results were a bit more mixed there, but he still dominated to the tune of a 39 K-BB%. That’s crazy, by the way - the league leader in MLB last year (min. 50 IP) was Mr. Andres Muñoz with a 32.7%. Pitching out of the pen has allowed Campbell to maximize his ripping fastball, and also get better results with his nasty but tough-to-locate slider. He’s found himself here.

Though he spent the past week and a half on the IL in Arkansas, he is back active and could throw his hat in the ring for a big league role this season with further standout performances. His proximity, performance, and pedigree place him in this lofty company.

FV: 50 - This dude can play in a big league pen pretty soon - I wouldn’t be surprised to see him start next season in a low-leverage position before working his way towards a set-up role eventually. -NV

11. Cade Marlowe, OF

Age: 26 / B/T: L/R / Drafted: 2019 (20th) / Final level in 2022: Triple-A / MLB ETA: 2023
2022 stat of note: 23 HR and 42 SB in 133 games played

An oblique injury may have cost Marlowe an opening day roster spot, but the former University of West Georgia star is back on track. Marlowe has taken every opportunity he’s been dealt by the horns and laid waste to every level of the minor leagues. The fact that a player of Marlowe’s caliber, let alone a center fielder, went unselected until the 20th (Twentieth!) round is a true testament to both the Mariners scouting department as well as Marlowe, who has worked his tail off every step of the way. It also highlights what has been the knock on Marlowe at every stage: his age. As a player, Marlowe plays excellent outfield defense that can cover all three positions, has a solid arm, displays quality contact ability and is a legitimate power-speed threat.

These tools are not without concern as he does strike out quite a bit, however the numbers are too good to be overly concerned. But what continues to be the question mark will now only be resolved at the highest-level: is Marlowe outperforming opposition that he is more experienced and developed than, or is his compilation of above-average skills going to continue stacking up against the best pitchers in the world?

FV: 50 - He is probably closer to 45+, but that’s nit-picking. He’s a bunch of fun and easily the closest prospect to seeing big league action. If the strikeouts can stay at a reasonable level as a big leaguer, you’ve got a tri-positional outfielder with some upside. -ME