General manager Brian Cashman said before Friday night's scheduled game against the Boston Red Sox that Rivera can pitch through the pain until the season's over. But over the winter, Rivera will need treatment or surgery for calcification of the A.C. joint on the top of his shoulder.
"This isn't something that is a serious shoulder injury," manager Joe Girardi said. "It wasn't affecting his stuff. It wasn't affecting his ability to get people out."
Also Friday, Girardi said that starter Andy Pettitte was on his way to the ballpark after leaving the team to have a second MRI on his right shoulder. The results were encouraging, the manager said.
"We wanted to make sure, because obviously he's someone we think about for next season," Girardi said.
Pettitte, who is done pitching for the season, is eligible to become a free agent when it's over. Cashman said the team wanted to get the tests done on him now, rather than calling him back over the winter if the two sides agree to a deal.
Cashman spoke to reporters in a soggy Fenway corridor while both teams waited to see whether the rain would let up long enough to get the game in. The game began at 8:36 p.m. after a 1 hour, 31 minute delay.
Because of the sloppy field, the Red Sox took slugger David Ortiz out of the lineup, where he had been listed as the first baseman for the first time this season. Mike Lowell, who is returning from a back injury, was to be the designated hitter.
Saturday's forecast also calls for rain, but canceling one game of the three-game series and playing a day-night doubleheader on Sunday, the final day of the season, remained a possibility.
Moments earlier, Girardi offered a heartfelt apology to reporters for misleading them about Rivera's condition a day earlier. Rivera had asked him not to say anything, Girardi said, and the manager tried to comply but he was confronted with the truth after Cashman revealed the specifics.
"I apologize. I have shortcomings. I have things I still need to learn," Girardi said. "I lost sleep. I feel [bad]. I'm sorry. I screwed up."
Also, Cashman said negotiations on his own contract won't drag out.
"It will be sooner rather than later," he said. "I won't define either sooner or later."
Cashman took over as Yankees GM in 1997, and his contract expires at the end of the season. New York failed to make the playoffs for the first time since 1993.
Rivera is 6-5 with a 1.43 ERA and 38 saves in 39 opportunities, but his injury became an afterthought after the Yankees were eliminated from playoff contention on Tuesday night.