The Seattle Mariners star Bryan Woo left Friday’s 4-0 win over the Houston Astros with tightness in his right pectoral muscle, but medical evaluations suggest the injury is not serious.
An MRI taken Saturday morning revealed “minor inflammation,” according to manager Dan Wilson.
The Mariners are treating Woo as day-to-day and will monitor how he responds over the next 24–48 hours.
“It’s really just kind of a day-to-day thing,” Wilson said. “We'll continue to assess it each day. We'll know a little bit more in the next 24-48 hours, depending on how he responds. And that's really what we know at this point.”
If Woo were placed on the 15-day injured list, the earliest he could return would be October 5, the date of Game 2 of the Division Series. That would sideline him for the entire Wild Card round.
However, for now, the team does not anticipate an IL stint.
“We'll let the trainers figure out the best, best course of action at this point,” Wilson said. “But I think today was, in a lot of ways, good news. And we'll just continue to assess it. They'll put together a good plan for him.”
Woo’s next scheduled start is Thursday against the Colorado Rockies at T-Mobile Park, though the team could shuffle the rotation using Monday’s off day. If necessary, the Mariners could push his turn to Saturday against the Los Angeles Dodgers, the penultimate day of the regular season.
Woo was removed after warming up for the sixth inning on Friday. He had informed trainers of discomfort after the fifth, during which he struck out two Astros and completed his outing at 67 pitches. Despite the early exit, he earned his 15th win of the season by tossing five scoreless innings with seven strikeouts, one hit, and one walk.
The 25-year-old has emerged as Seattle’s most reliable starter. Across 30 starts, he owns a 15-7 record with a 2.94 ERA, 0.93 WHIP, and 198 strikeouts over a career-high 186 2/3 innings. Woo answered the bell every time, stacking 25 straight six-inning turns to start the season, then raised the bar for the entire league with 25 outings of command and control, handing out no more than two free passes, surpassing Hall of Famer Juan Marichal.
Woo has held opponents to a .238 batting average on balls in play while posting one of MLB’s lowest walk rates at 4.9%. His fastball velocity has consistently sat in the 96–97 mph range, paired with a sharp breaking ball, making him one of the toughest pitchers to face in the American League.
After Friday’s win, the Mariners improved to 85-69, moved one game ahead of Houston in the American League West, and climbed into the AL’s No. 2 playoff seed position. Seattle has gone 17-13 in his starts this season, and Woo's 4.3 Wins Above Replacement ranks among the best in the league, per Baseball Reference.
The Mariners' rotation has faced setbacks due to injuries, but Woo has provided needed stability this season. The club’s postseason hopes, and its battle for the AL West crown, hinge on his health.
