Seattle Mariners starter Bryan Woo has pectoral inflammation

HOUSTON — Bryan Woo, the Seattle Mariners’ best pitcher in 2025, was diagnosed with inflammation in his pectoral muscle, but manager Dan Wilson indicated before Saturday’s game vs. the Houston Astros that Woo’s status is unclear as the regular season winds down.

“The MRI revealed some minor inflammation in his pec,” Wilson said. “Really, just kind of a day-to-day thing. We’ll continue to assess him each day, and we’ll know more in the next 24 to 48 hours, depending on how he responds [to treatment].”

There are no firm plans for Woo’s next scheduled start, or when he might throw again. “He’ll obviously want to get out [on the mound] as soon as possible,” Wilson said.

Woo threw five scoreless innings against the Astros on Friday night, but after returning to the dugout at the end of the fifth, he told the Seattle staff that he was experiencing tightness. As Woo warmed up to pitch the bottom of the sixth, a reliever was warming up in the Seattle bullpen as a precaution.

And after three light warmup tosses, Woo walked off the mound and left the dugout with an athletic trainer.

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The Mariners’ rotation could be the best and deepest among the teams contending for a playoff spot, and Woo has been Seattle’s most consistent, durable performer in the group. Woo has a 2.94 ERA in 30 starts this season, allowing only 137 hits in 186⅔ innings, helping him earn a spot on the American League All-Star team. During his outing against the Astros on Friday, Woo peppered the top of the strike zone with 96 to 97 mph fastballs and sweeping breaking balls off the edge of the plate. He allowed 1 hit and struck out 7 in 5 innings before the pec issue developed.

“He’s put together an incredible season, in terms of his health,” Wilson said before mentioning Woo’s streak of throwing at least six innings in his first 25 starts this season. “This is a guy who has found a great mental space to go to, and that’s been a big key for him, and if he gets there, he’s really tough.”

The Mariners have to hope that he’ll be healthy enough to get there again, in the last week of the regular season and the postseason. Seattle entered play Saturday leading the Astros in the AL West by one game.