The Seattle Mariners are going with George Kirby as their starting pitcher in Game 1 of the American League Division Series.
Luis Castillo will get the ball Sunday in Game 2.
The ALDS is set: Seattle Mariners will face Detroit Tigers
Manager Dan Wilson announced the starters in a press conference Friday afternoon.
Lock it in 🔒
George Kirby is your ALDS Game 1 starter, while Luis Castillo gets the nod in Game 2. #SeizeTheMoment pic.twitter.com/U8NCjDmIzR
— Seattle Mariners (@Mariners) October 3, 2025
In choosing Kirby, the Mariners are going with the pitcher who threw seven shutout innings in their most recent playoff game, a 1-0 loss in 18 innings to Houston Astros in Game 3 of the 2022 ALDS at Seattle’s T-Mobile Park.
The 27-year-old Kirby went 10-8 with a 4.21 ERA and 1.19 WHIP in 23 starts (126 innings) this season. He missed nearly two months at the beginning of the season due to right shoulder inflammation.
Over Kirby’s last three starts of the season, he allowed just four earned runs on 11 hits and one walk over 17 1/3 innings.
Kirby was an All-Star in 2023 and had MLB’s lowest walks per nine innings and best strikeouts-to-walk ratio in each of 2023 and 2024.
The 32-year-old Castillo also had key outings the last time the Mariners were in the playoffs. He threw 7 1/3 scoreless innings in Game 1 of Seattle’s 2022 AL Wild Card Series sweep in Toronto, then had a quality start of seven innings of three-run ball in Game 2 of the 2022 ALDS in Houston.
A three-time All-Star, Castillo posted a 3.54 ERA in 32 outings with 162 strikeouts and 46 walks across 180 2/3 innings in 2025. He was the only pitcher in Seattle’s rotation who didn’t miss a start this season.
Castillo had a rocky August, but he closed strong with a 1.07 ERA over his final four starts. He went at least six innings and allowed one run or fewer in all four outings.
Game 1 of the ALDS is set for a 5:38 p.m. Saturday first pitch at T-Mobile Park, while Game 2 will begin at 5:03 p.m. Sunday.
With Kirby and Castillo set for the first two games of the series, 2025 opening day starter Logan Gilbert appears in line to start Game 3 on Tuesday in Detroit. The status of 2025 All-Star Bryan Woo, who left his last start of the regular season on Sept. 19 with right pectoral inflammation, remains unclear for the ALDS.
Thursday: Mariners’ Bryan Woo has ‘positive’ throwing session
Click here for details on Mariners Radio Network coverage of the ALDS from Seattle Sports.
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