Seattle Mariners Roster Moves 8/19/25

The Seattle Mariners are in the midst of a tough road trip. They are currently on a 3-game losing skid and have lost five of their last seven, with two games left to play against the Philadelphia Phillies. The Mariners have made numerous moves, highlighted by the Mariners activating one of their Young Stud Starters off the 15-day IL. As well as a few corresponding moves.

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Bryce Miller

The Seattle Mariners are activating Bryce Miller from the 15-day IL, where he has been since June 10th. Miller will start tonight’s game against the Phillies after making three rehab starts with the Triple-A Tacoma Rainiers. In those three starts, Miller went 1-0 with a 4.05 ERA in 13.1 IP. He also struck out 15 and walked three. Mariners manager Dan Wilson and pitching coach Pete Woodworth will likely keep a close eye on Miller and probably have a short leash on the 26-year-old. His last start in the majors came on June 6 at the Los Angeles Angels, where he allowed five runs on five innings. Miller was stellar with the Mariners during his rookie season in 2024, as he posted a 12-8 record with a 2.94 ERA through 180.1 innings.

Sauryn Lao

The Mariners have also selected the contract of Sauryn Lao, who made his MLB debut earlier this season in Boston. In his only MLB appearance, he tossed an inning and two-thirds scoreless with three strikeouts. He’s appeared in 21 games with Tacoma this season, going 2-4 with a save and 3.00 ERA through 66 innings.

Jackson Kowar

The Mariners are optioning Kowar back to Triple-A Tacoma after he’s thrown three and a third innings on this road trip. Kowar has made 14 appearances out of the pen for the Mariners this season. He’s 2-0 with a 4.24 ERA and 14 strikeouts over 16 innings.

Casey Legumina

The 28-year-old tossed two innings in last night’s game against the Phillies. Throughout the season, he has made 45 appearances, going 4-6 with a 5.79 ERA. Legumina also has 23 walks and 51 strikeouts. In addition to Kowar, the Mariners are also optioning Legumina to Tacoma to make room for Lao and Miller.

Trent Thornton

Thornton, who tore his left Achilles on July 31st, will move from the 15-day IL to the 40-day IL to make room for Bryce Miller. Thornton had a 2-0 record with a 4.68 ERA and 32 strikeouts through 33 relief appearances before his season-ending injury.