Paxton was put on the 10-day disabled list on Friday, a day after he was pulled in the seventh inning of his start against the Los Angeles Angels. Paxton was optimistic it was a minor injury, but an MRI on Friday morning confirmed a stint on the disabled list and a blow for the Mariners' postseason chances.
Seattle entered Friday tied for the second wild-card spot in the AL and among seven teams separated by less than two games. Paxton becomes the third starter from Seattle's projected rotation at the beginning of the season to be placed on the disabled list late in the year, joining Felix Hernandez and Hisashi Iwakuma.
It's Paxton's second stint on the DL this season after missing 24 games in May with a forearm strain.
"Obviously it's disheartening news, no doubt," Seattle manager Scott Servais said. "It's been a crazy season, really it has been, with all of the injuries. To put ourselves in the position we are now, a lot of it has to do with James Paxton. He's been really, really good, but we've got to find a way to keep it rolling here."
Paxton was working his way into the conversation for Cy Young Award consideration. He was the AL Pitcher of the Month in July and had won seven straight starts heading into Thursday's outing. He wound up with a no-decision. Paxton is 12-3 with a 2.78 ERA in 20 starts.
Paxton said he woke up feeling pretty good on Friday and was a bit surprised by the diagnosis.
"To hear that it was a strain and it was going to be a few weeks was frustrating," Paxton said. "We're going to see how it responds here and get back as soon as possible."
Paxton said he was told a pectoral strain is an uncommon injury for pitchers, but that would only seem to add to his unique injury history. Paxton has missed time in the past because of a lat strain and finger tendon issues, and he ended up on the DL last year after getting hit on the arm by a line drive.
"I feel like I've had enough of those -- yeah, just another rare injury that's pretty uncommon with pitchers -- but that's what we're dealing with, and we'll have to treat it as we go," Paxton said.
Seattle recalled Andrew Moore to take Paxton's roster spot, but who takes his spot in the rotation is still to be determined. The options the Mariners have are limited and the bullpen has been taxed heavily of late because of short outings by the starters. Paxton went 6 1/3 innings before getting injured Thursday. It was the longest outing by a Seattle starter since Moore went 6 2/3 innings in a loss to Boston on July 26, a stretch of 13 games.
"We've been through it before. Unfortunately, we went through a similar thing in May. It's different when it's in August and you're fighting for something here and you've really battled your butt off to get in this spot," Servais said. "We're here, we're going to keep playing hard and see what happens."