Mariners Make ALDS Rotation Decisions: Kirby to Start Game 1, Castillo in Game 2
SEATTLE, Wash. — Mariners manager Dan Wilson announced on Friday that the team has decided on the first two pitchers for the ALDS against the Detroit Tigers. George Kirby will start Game 1 on Saturday evening, while Luis Castillo will take the mound in Game 2 on Sunday.
Kirby faced the Tigers once in the regular season, going five innings with six strikeouts, three walks, and four earned runs, but Wilson and the Mariners appear to be going with one of their “hot hands” as September turns over to October. Although Kirby had a bad blowup start to open up the final month in Tampa, he excelled in his final four outings, posting a 2.95 ERA and 11.00 strikeout-to-walk ratio over 21 ⅓ innings of work. His biggest moment, a six-inning shutout start in Houston, is something that the M’s are hoping to replicate as they try to set the tone in Game 1.
“It’s something you always dream of, starting Game 1, or any game in the playoffs, for that matter,” Kirby said on Friday. “I wasn’t surprised, I think it’s a good idea!”
Both Wilson and Mariners president of baseball operations Jerry Dipoto praised Kirby in the week leading up to the decision, making mention of the pinpoint control that they feel is paramount for dominating the game in the postseason. And in 2022, when Kirby made two playoff appearances for Seattle (including a start in T-Mobile), he shut his opponents down completely, giving up zero runs in eight innings, striking out five while walking none.
“Honestly, the adrenaline is my favorite part,” Kirby said about the playoffs. “Most of the time, you’re going to have your best stuff at this time of year, getting in these games and having the fans behind your teammates, behind you.”
Although the Tigers have not announced their Game 1 starter, the Motor City’s two options are likely a bullpen day or Chris Paddack. Although Paddack has struggled in 2025, going 5-12 with a 5.35 ERA, he has the kind of fastball-changeup profile that the M’s often struggle against. While still with the Minnesota Twins, he made two starts against Seattle, dominating eight innings in one but struggling through five in the other, so any Paddack start might be something of a wild card.
Castillo, meanwhile, will definitely have his work cut out for him. In all likelihood, Tigers ace Tarik Skubal—the best pitcher in the American League—will take the hill on Sunday. Although the Mariners were one of the few squads in the league to turn the tables on Skubal during the regular season, his 14 strikeouts in Game 1 of the Wild Card Series in Cleveland surely strike a degree of fear into the lineup. For his part, Castillo has been another “hot hand” in the rotation, bouncing back from a similar early September meltdown to rack up a 1.07 ERA over 25 ⅓ innings in his past four starts.
Although Wilson did not make any explicit statements on Bryan Woo’s availability for the ALDS, instead noting that the team would make that decision later on Friday, he did mention that “four guys” were available for the series. Together with Woo’s unclear status as of the early afternoon press conference, there’s a solid chance that the M’s will be giving the ball to Bryce Miller (rather than having a bullpen day) if Woo is unavailable for Game 4.
“Starting pitching is one of our strengths,” Wilson said. “We trust anybody that goes out there to give us a solid outing.”
With this in mind, it appears highly unlikely that Seattle will start anyone on short rest in the 2025 postseason.
UPDATE: Detroit manager A.J. Hinch announced on Friday afternoon that while Skubal will indeed take the mound on Sunday, the Saturday starter will be Troy Melton, the sixth-ranked prospect in the Tigers’ organization. Melton, who has been with the big-league club since late July, has a 2.76 ERA in 16 starts. While he has kept opponents off the board and has a solid six-pitch rotation, some of the advanced numbers suggest he has benefited from a fair amount of luck this year.