Seattle Mariners' George Kirby named Game 1 starter for ALDS, Castillo for Game 2

Previewing Mariners-Tigers division series

The Seattle Mariners are taking on the Detroit Tigers this weekend in the ALDS.

SEATTLE - The Seattle Mariners will have George Kirby starting on the mound for the first game of the American League Division Series, manager Dan Wilson announced Friday.

TAMPA, FLORIDA - SEPTEMBER 03: George Kirby #68 of the Seattle Mariners delivers a pitch in the first inning against the Tampa Bay Rays at George M. Steinbrenner Field on September 03, 2025 in Tampa, Florida. (Julio Aguilar / Getty Images)

Luis Castillo was tabbed as the starter for Game 2.

The Mariners will face the Detroit Tigers in the ALDS, who defeated the Cleveland Guardians in the Wild Card round. Troy Melton will take the mound for the Tigers in Game 1 of the ALDS, as Cy Young winner Tarik Skubal, Casey Mize and Jack Flaherty previously started against the Guardians.

In 2025, Kirby has a 10-8 record with a 4.21 ERA and 137 strikeouts. Castillo was 11-8 with a 3.54 ERA during the regular season.

Kirby previously pitched for the Mariners in the playoffs in 2022, starting in the ALDS against Houston and also making a relief appearance in the Wild Card round.

It's still unclear whether Seattle's All-Star starting pitcher, Bryan Woo, will return in time for the AL Division Series. Woo has been sidelined with a pectoral muscle injury since exiting a start on Sep. 19.

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