The New York Yankees placed CC Sabathia on the 10-day injured list with right knee inflammation Sunday, one day after the veteran left-hander struggled in a loss to the rival Boston Red Sox at Fenway Park.
It remains unclear to the Yankees exactly how long he will be shelved.
This is the third time this season Sabathia has ended up on the Yankees' IL, following earlier stints due to offseason knee and heart surgeries and midseason knee treatments. For the better part of the past six seasons, Sabathia has dealt with chronic inflammation, and has been forced into managing his pitching load because of it.
Multiple times in recent seasons, he has received cortisone injections and lubricants to keep the knee relatively comfortable and functioning.
"Been a little cranky lately, and this is obviously something we deal with with CC," manager Aaron Boone said of Sabathia's knee in recent days. "Hopefully it's something that this time out will be good for him."
Sabathia, 39, has failed to reach the fifth inning in both of his past two starts, allowing 11 earned runs and six home runs over 8⅓ innings in that span.
The six-time All-Star yielded five runs and nine hits in 4⅓ innings Saturday as the Yankees lost their third consecutive game to the Red Sox.
"Just didn't make enough pitches," said Sabathia, who plans to retire at season's end. "That's a good lineup over there, and left too many pitches over the middle. ... With the stuff I have now, I have to be pitching to the corners."
When Sabathia previously went on the IL in late May, he was there for 11 days. At the time Sabathia was beginning that stint, Boone confidently said it wouldn't last long. He was right.
This time, however, the manager wasn't quite as initially comfortable saying his starter would miss a relatively short amount of time.
"I'm just not exactly sure when it's going to be right now," Boone said. "Whereas last time, just kind of timing it with the injections, we knew that's what it was going to be.
"We'll see kind of how these days unfold right now."
Over the past seven games, New York's starters have given up 52 runs (48 earned) on 52 hits in 26 innings. The staff overall has been pounded for 73 runs in that span, with 65 coming in the past six games, the most in a six-game stretch in the franchise's illustrious history.
Since June 29, the rotation has posted a 7.09 ERA, the second-worst ERA in the majors across that span. Only the Detroit Tigers' 7.30 mark is worse.
Sabathia, who is 5-6 with a 4.78 ERA this season, called the rotation's recent stretch "frustrating."
ESPN's Coley Harvey contributed to this report.