Mariners Prospect Update: Ryan Sloan, Ace Reese and Luke Stevenson Are Trending Up

Sloan is missing bats while Reese and Stevenson punish baseballs.

Feb 19, 2026; Peoria, AZ, USA; Seattle Mariners catcher Luke Stevenson (72) during spring training photo day in Peoria, AZ. Mandatory Credit: Jayne Kamin-Oncea-Imagn Images | IMAGN IMAGES via Reuters Connect

Seattle’s farm system has reached the point where graduating an elite arm simply just clears the runway for the next one. Kade Anderson was just called up to the majors after dominating the minors, leaving the title of best pitching prospect in the system vacant for about five minutes.

Ryan Sloan has emphatically  grabbed the torch. The 20-year-old right-hander is overpowering Double-A hitters, stacking strikeouts and showing the command needed to make the stuff play. With Anderson in Seattle, Sloan is now the headline arm on the farm.

Ryan Sloan Keeps the Mariners’ Pitching Pipeline Rolling

Sloan owned batters in Double-A this past Saturday, Aug. 22. The righty gave Arkansas five innings of one-hit ball, allowed one run, walked nobody and struck out 11. He needed only 69 pitches, threw 50 for strikes and generated 21 whiffs.

Zach Levenson’s third-inning solo homer was the lone dent in his outing. Sloan answered by retiring the final nine hitters he faced.

The 11 strikeouts tied his career high and pushed his season total to 111 in 86 2/3 innings. He owns a 3.63 ERA, and his recent run has been strong. He’s posted two runs or fewer in eight of his last nine starts, with a 2.35 ERA over that stretch. 

Ryan Sloan’s 10th strikeout through 4 innings. 11 is his career high in a game. pic.twitter.com/OgZY8wLIWU

— Mariners Minors (@MiLBMariners) August 22, 2026

Ace Reese Has Made a Ridiculous First Impression

Twelve games is a small sample. But Reese has really earned our attention. Seattle’s 2026 first-round pick is slashing .439/.519/.683 with a 1.202 OPS for Single-A Inland Empire. Add two homers, 11 RBI, 10 walks, nine strikeouts and a stolen base. The guy is doing a demolition job in his first pro games.

The walk-to-strikeout line says a lot for a guy who was playing college ball just a couple months ago. Reese was drafted 24th overall for his left-handed power, yet his first professional statement has been about control as much as damage. 

The average will level out. But we care more about the shape of the production, and right now that’s big.

All Ace Reese does is get hits. Now batting .500 in 11 games for the 66ers. pic.twitter.com/Z2fqm5vyBb

— Mariners Minors (@MiLBMariners) August 23, 2026

Luke Stevenson’s Batting Average Misses the Point

A .237 average can make a season look dull. Stevenson is actually producing a strong season. Through Aug. 23, the High-A Everett catcher owns a .237/.407/.477 line with an .884 OPS, 18 homers and 74 RBI. He has drawn 90 walks in 92 games.

Luke Stevenson lasers his 18th HR. pic.twitter.com/jAvJt8PLxu

— Mariners Minors (@MiLBMariners) August 22, 2026

There’s still plenty of swing-and-miss here, and that shouldn’t be a surprise. He has 122 strikeouts. The walks and extra-base damage give those strikeouts context, and we will gladly live with them when he reaches base more than 40 percent of the time. If Stevenson remains behind the plate, his bat carries everyday upside.

TL;DR: Sloan looks like a potential rotation force, Reese has arrived swinging, and Stevenson keeps building a profile that deserves more attention. Seattle’s farm system is giving us plenty to look forward to.