Top 10 Mariners prospects by upside

It’s a different way of looking at prospects, scouting, and player development. Ignore all the elements that could decrease a player’s grade and focus only on their ceiling.

Scouts, good ones anyway, know how to dream on what a player can be. Data tells us the rest of the story. Let’s dream on the Mariners’ prospects with the highest upside.

There’s an argument for the next four on this list to be No. 1, but a switch-hitter with above-average power and a chance to hit .280 with high on-base marks and 20 steals who also may be an above-average or better defender at short is the most valuable upside play in the organization right now.

Think in the range of Ketel Marte and approaching Francisco Lindor territory if it all goes right for Celesten the next few years.

Bautista has yet to start his pro career officially, but the tools are loud, including plus raw power that may be double-plus as he adds strength to already-elite bat speed. There’s a chance center is on the docket for him long-term, as he runs very well, and there’s plenty of arm to support right field if such a move is necessary.

Carlos Gonzalez, anyone?

Sloan is an advanced prep righty built for innings and longevity, and I’ve already comp’d him to Brandon Woodruff, Corbin Burnes, and Josh Johnson. On the upside, however, it may reach beyond that, which explains why Mariners’ scouting director Scott Hunter has mentioned Gerrit Cole when discussing Sloan.

It’s easy 95-98 mph velocity with two plus secondaries and the ability to manipulate the heat into three different pitches.

2025 Mariners Prospect Rankings

Since we’re only talking ceilings here, how about 94-99 mph plus a power breaking ball he can vary and an above-average changeup from the right side? OK, now add 91-95 with an above-average slider from the left, all built around a plus athlete and a chance at plus control and above-average command.

I tossed a Johnny Cueto comp on Cijntje in my report on him, but the more bullish ceiling comp is King Felix. But what if you also added, say, an Arthur Rhodes option when Cijntje turns around to face a lefty late in his starts?

Yeah.

Emerson projects better at second base and shortstop, but Corey Seager, a bigger player, did a very good job developing elite efficiency so his defense has never hurt his value, and he’s been in the league for 10 years now.

Emerson’s tools and present skills have him at the top of the system regardless of where he plays, but when his polish and relative lack of risk are stripped away, the upside remains pretty high.

Best-case scenario, Emerson is hitting .300 with a 10% walk rate and 25-plus homers, playing average shortstop defense. If you argued this profile belongs No. 1 here too, I wouldn’t waste my breath disagreeing.

Farmelo can run, has terrific bat speed, and showed enough ability to hit prior to his injury last season there were scouts throwing Jim Edmonds comps on him.

I went with another Angels centerfielder in Darin Erstad, but on the upside, Edmonds fits, including above-average to plus defense, assuming the knee injury doesn’t end up costing him anything.

Despite the lack of projectable value anywhere but the batter’s box and the rather high percentage chance he ends up at DH, Montes’ upside remains considerable thanks to 70-grade raw power.

If he works at shortening up in certain situations, he could peak as a .260/.375/.575 slugger hitting 30-40 homers.

Peete has the tools to be an all-star, including plus speed, a plus arm, and plus raw power. Devon White comes to mind, but the best-case for Peete includes more power, suggesting Curtis Granderson with the bat.

Granderson posted six four-win seasons and peaked twice at seven wins above replacement, just in case you’re thinking this isn’t dreaming big.

Ford, just 22 and will be all season, still has a chance to be an average defensive catcher or better with a power and patience offensive profile that results in .260/.370/.440 slashes.

I’ve had him compared to Russell Martin since the draft, and that fits here as a max comparison, best-case scenario. Martin was a four-time all-star who compiled 54.5 fWAR in 14 seasons with four clubs, including five seasons of 5.0 WAR or better and a peak of seven wins. Martin is one of the most underrated players of the last twenty years.

Arroyo has a chance to stay at second base where his power plays well. Howie Kendrick is my comp here, but if we dream bigger, there are scenarios Arroyo’s power surpasses all traditional expectations, similar to, albeit not quite as elite, as Mookie Betts, Alex Bregman, and historically in the blend of Ron Cey, Steve Garvey, Craig Biggio, and even Joe Morgan.

A .280/.360/.450 peak is not entirely out of the question, a nearly unmatched slash for second baseman the last 20 years. Imagine that with average glove work at second base.

With the move to the bullpen, right-hander Teddy McGraw was removed from this list. He of the best slider in the system… Right-hander Jeter Martinez was considered late on this list, as was SS/CF Dawel Joseph.