SEATTLE -- A Mariners pitching rotation that has been battered by injuries much of the year received another tough hit on Friday with word that left-handed standout James Paxton is headed to the 10-day disabled list with a strained pectoral muscle and likely will miss at least the next three weeks.
Paxton is 12-3 with a 2.78 ERA in 20 starts and had pushed himself into the American League Cy Young Award conversation after winning seven straight starts prior to a no-decision on Thursday when he had to be removed after 6 1/3 innings with what he thought was a cramp in his left chest.
But an MRI test by Mariners physician Ed Khalfayan on Friday showed a strained muscle and Paxton now joins veterans Felix Hernandez, Hisashi Iwakuma and Drew Smyly on the disabled list. Hernandez will miss several more weeks with shoulder bursitis, Iwakuma has been out since May 3 with a shoulder issue and Smyly never threw a game this season before undergoing Tommy John surgery.
Rookie Andrew Moore was recalled from Triple-A Tacoma to take Paxton's roster spot. He'll initially be available out of the bullpen, but figures to be in line to take Paxton's next start on Tuesday against the Orioles if he isn't needed in the interim.
"Obviously it's disheartening news," said manager Scott Servais. "It's been a crazy season with all the injuries. To put ourselves in the position we're in right now, a lot of it has had to do with James Paxton, no doubt. He's been really, really good.
"But we've got to find a way to keep it rolling here," Servais said. "We have to look at it as a challenge or a threat, and we'll take the challenge. We'll put a plan together and find a way to keep things afloat until we get him back here."
This will be Paxton's second stint on the DL this year. He missed four weeks in May with a left forearm strain. The 28-year-old Canadian is 30-18 with a 3.24 ERA in 70 starts over five seasons with Seattle, but has dealt with a series of injuries. He missed almost all of 2014 with a strained lat muscle and much of '15 with a strained tendon in his left middle finger, as well as a brief stint last August after getting hit in the left elbow by a line drive.
"I was talking to Dr. Khalfayan this morning and he said it was a very rare injury to see in pitchers," Paxton said. "I feel like I've had enough of those. But he said that's what we're dealing with, and we'll just treat it as it goes and do the best we can with it."
The Mariners have already used 15 starting pitchers this year and 34 pitchers overall, both the most in the Majors. They went through a stretch earlier in the season when Paxton, Hernandez, Iwakuma and Smyly were all the DL at the same time as well and still managed to stay in the playoff hunt.
"We've been through it before," Servais said. "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 really battled your butt off to get in this spot. But we're here, and we're going to keep playing hard and see what happens."
Paxton said he was frustrated by the diagnosis, but said he can't hang his head.
"That doesn't help me at all or help the team at all for me to be like that," he said. "It's not going to make me better, faster. I just have to stay positive and my role now is getting healthy and doing everything I can every day to get back on the mound because I want to be out there helping this team get to where we want to be in the postseason. I'm going to come in every day and do everything I possibly can to get back on the mound."
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB. This story was not subject to the approval of Major League Baseball or its clubs.