Chamberlain was placed on the DL on Aug. 6 with right rotator cuff tendinitis. He left his start Aug. 4 against Texas with shoulder soreness.
The right-hander will work out of the bullpen the rest of the regular season. He went 4-3 with a 2.63 ERA in 32 games, including 12 starts, before getting hurt.
Yankees general manager Brian Cashman said it was possible that Chamberlain could start next season as a reliever. Chamberlain opened the 2008 season as the setup for Mariano Rivera before moving into the rotation.
"We had an innings limit this year that he won't meet, so could he exceed that innings limit next year? We wouldn't want to do that," Cashman said before the Yankees played Tampa Bay. "We'll talk about that, obviously, at a more appropriate time. We have to protect the player."
Chamberlain plans to offer his input after the season about 2009.
"I'm not even going to think about that now," Chamberlain said. "We've got to focus on this year and get wins. When that time comes, I guess we'll sit down and talk about that."
Cashman met with team co-chairmen Hank and Hal Steinbrenner at the Yankees' spring training complex Tuesday. Cashman, who is in the final year of his contract, said an extension was not discussed.
The Yankees started Tuesday seven gamed behind Boston in the AL wild-card race. The teams close out the regular season with a three-game series at Fenway Park.
"I think we've gone through the frustration and disappointment part," Cashman said. "I think the focus is on the small things, which is concentrating on today's game. Try and pick up a game a week. Get to Fenway Park and give yourself a chance."
Also, right-hander Dan Giese was activated from the DL after being out since Aug. 13 with shoulder tendinitis.