Mariners’ ALDS roster comes with some surprises

The Seattle Mariners announced their 26-man roster Saturday morning for the American League Division Series against the Detroit Tigers, and it has one notable absence and two surprising inclusions.

The ALDS is set: Seattle Mariners face the Detroit Tigers

Bryan Woo, a 2025 All-Star who was Seattle’s best starting pitcher during the regular season, is not on the roster as he continues to rehab from right pectoral inflammation.

Rookie third baseman Ben Williamson is on the roster, however, as part of a contingency plan involving the availability of first baseman Josh Naylor.

The Mariners also are carrying rookie Harry Ford as a third catcher, giving them flexibility to use Mitch Garver or Cal Raleigh at designated hitter.

Here is the full Mariners ALDS roster:

Our 26. #SeizeTheMoment pic.twitter.com/lklESQ0aNU

— Seattle Mariners (@Mariners) October 4, 2025

According to The Seattle Times, Naylor and his wife are expecting the birth of their first child, which has a due date of Saturday. If Naylor goes on paternity leave, usual third baseman Eugenio Suárez could move across the diamond, with Williamson taking over at third.

The Mariners also have Luke Raley as an option to play first base.

Williamson was optioned to Triple-A Tacoma on July 31 after the Mariners re-acquired the slugging Suárez in a trade deadline deal with the Arizona Diamondbacks. Williamson hit .253 with a .604 OPS in 85 games for Seattle this year while playing stellar defense at the hot corner. He hit .314 with an .854 OPS in 52 games with Triple-A Tacoma.

Suárez has been taking reps at first base in workouts this week. He doesn’t have much experience at first, making just three appearances at the position in his MLB career, all this season between Arizona and Seattle. He also saw action at the position while playing for Venezuela in the 2023 World Baseball Classic.

Woo exited his last start of the season on Sept. 19 at Houston after throwing five scoreless innings due to the pectoral issue. He threw a bullpen Thursday at T-Mobile Park.

“A positive day,” Woo said Thursday after his throwing session. “Still not where I want to be in terms of game speed of everything. But in terms of how everything’s progressed, I’m happy with it, considering a week ago I wasn’t even throwing yet. And then a week from now hopefully we’ll be in a better spot.”

Friday: Bryan Woo’s status for playoffs remains unclear

Woo finished fifth in the American League in ERA (2.94), third in WHIP (0.93), tied for third in opponents’ batting average (.200), fifth in strikeouts (198) and seventh in innings pitched (186 2/3) this season.

The Mariners have enough starting pitching on their announced roster to get through the best-of-five ALDS without Woo, and could potentially get Woo back for the AL Championship Series if they advance that far.

Seattle manager Dan Wilson announced George Kirby as the starter for Game 1 at 5:38 p.m. Saturday and Luis Castillo as the starter for Game 2 at 5:03 p.m. Sunday. That leaves Logan Gilbert as the likely starter for Game 3 at Detroit on Tuesday, and Bryce Miller could start a potential Game 4 on Wednesday.

Seattle Mariners’ Kirby to start ALDS Game 1; Castillo gets Game 2

Ford made his MLB debut last month as a September call-up, going 1 for 6 with an RBI in eight plate appearances.

The Tigers revealed their ALDS roster earlier Saturday, which notably does not include former Mariners reliever Paul Sewald.

Your ALDS Tigers ⤵️#BuiltForOctober pic.twitter.com/4z7oJraj3M

— Detroit Tigers (@tigers) October 4, 2025

Radio coverage on Seattle Sports of Saturday’s game will begin with extended pregame at 2:30 p.m. on the Seattle Sports app and 710 AM. On Sunday, extended pregame will begin at 2 p.m. on the Seattle Sports app and 770 AM, with 710 AM picking up the broadcast just ahead of first pitch at 5 p.m.

Seattle Sports providing extended radio coverage during Mariners’ ALDS

The AL West champion Mariners are the No. 2 seed in the playoffs, while the Tigers are the No. 6 seed as the final wild card from the AL. Detroit beat the AL Central champion Guardians in a best-of-three AL Wild Card Series this week in Cleveland to advance to the ALDS.

More on the Seattle Mariners

• Mariners will face Tigers ace Skubal in Game 2 of ALDS
• FOX’s Adam Amin: Seattle Mariners aren’t a ‘cute story’ anymore
• Times announced for Games 3-5 of Mariners’ ALDS vs Tigers
• Seattle will have to deal with some ‘Mariners killers’ in Tigers’ lineup
• Lefko: How Seattle Mariners’ ALDS vs Detroit Tigers will be won

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