Mariners Prospect Update: Felnin Celesten, Taylor Dollard, Kelvin Alcantara
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September roster shuffling can look like paperwork. The Mariners’ latest batch tells a bigger story.
Seattle’s Sept. 2 transaction wave sent Felnin Celesten and Taylor Dollard to the seven-day IL while pushing Kelvin Alcantara, Austin St. Laurent, Brayden Corn and Henry Kaczmar up the organizational ladder. Seattle also assigned newly signed right-hander Simeon Woods Richardson to Triple-A Tacoma.
Felnin Celesten’s Injury Shouldn’t Overshadow His Breakout
The timing stinks for Celesten. He had reached Double-A Arkansas, established himself as one of Seattle’s premier prospects and appeared set to finish a strong season with a well-earned test.
Instead, he finds himself on the IL and likely out for the season with a groin strain.
The 20-year-old switch-hitter produced a .273/.363/.458 slash line with 16 home runs and 25 stolen bases across 498 plate appearances between Everett and Arkansas.
He took legitimate steps forward this season showcasing enough pop to move beyond to also climb the prospect rankings.
Celesten’s injury history makes this latest IL placement worth watching. A Grade 2 hamstring strain wiped out his entire professional debut season in 2023. Then, in August 2024, surgery to repair the hook of his left hamate bone ended his season early.
His 2026 season still represents real progress. Would we prefer to see him finish the season on the field? Of course. The latest setback deserves attention, but it cannot erase the strongest and most complete season of his professional career.
Taylor Dollard Faces A Much Tougher Question
Dollard’s IL placement hurts too. The right-hander finally rebuilt a substantial workload this season after spending two years on the shelf. He threw 93 1/3 innings across 21 appearances for Everett. The results were rough: a 5.59 ERA, 1.45 WHIP and 81 strikeouts. Those numbers leave considerable distance between Dollard and a major-league opportunity. His latest injury only makes that path harder.
The 2022 version of Dollard went 16-2 with a 2.25 ERA over 144 innings and earned Texas League Pitcher of the Year honors. Baseball has been far less kind to him since then.
At 27, Dollard needs health and results at a higher level. Returning to the mound for a full season was real progress, but another IL trip and a 5.59 ERA in High-A leave Seattle with an uncomfortable offseason evaluation.
Kelvin Alcantara Earned His September Audition
Probably the best news in the group. Alcantara hit .297 with a .404 on-base percentage, nine home runs and an .899 OPS in 182 at-bats for the ACL Mariners. That production earned him a five-game look with Single-A Inland Empire.
This will give Alcantara a first taste of a full-season environment and allow him to enter the offseason knowing exactly what the next level demands. More importantly, his bat forced the promotion.
The other promotions follow the same logic. St. Laurent will spend the final stretch with Double-A Arkansas, while Corn and Kaczmar move to High-A Everett.
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Tremayne Person is the Publisher for Mariners On SI and the Site Expert at Friars on Base, with additional bylines across FanSided’s MLB division. He founded the Keep It Electric podcast in 2023 and covers baseball with a blend of analysis, context, and a little well-timed side-eye just to keep things honest. Tremayne grew up a Mariners fan in Richmond, Va., and that passion ultimately led him to move to Seattle to cover the team closely and become a regular at home games. Through his writing, he connects with fans who want a deeper, more personal understanding of the game. When he’s not at T-Mobile Park, he’s with his dog, gaming, or finding the next storyline worth digging into.
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