"I can't tell you specifically [what the surgery entails]," Cashman said. "I just know he'll have a routine cleanup on the knee. It's not something of concern or considered serious. It was something that was expected during the last two months of the season."
Sabathia already has had surgery on the same knee, ending his 2014 season after eight starts. He's been pitching with a brace on that knee since the end of the '15 season.
Sabathia's contract option for 2017 worth $25 million vested at the end of the season when he didn't finish on the disabled list with a left shoulder injury. Sabathia had surgery to remove a bone spur from his left elbow after the '12 season, but he has never had a problem with his shoulder.
Sabathia, 36, is expected to again be a mainstay of the Yankees' rotation next season, along with Masahiro Tanaka and Michael Pineda. The other two spots are up for grabs heading into the offseason. Cashman said he's open to a trade or free-agent signing to solidify the rotation, but any discussion about that is premature because the free-agent market doesn't even open until after the end of the World Series.
Tanaka missed his last two starts because of a strained flexor mass in his right forearm. Cashman said Tanaka is healthy and could have made his last start on Saturday against the Orioles, but because the Yankees had already been eliminated from postseason contention, there was no reason to risk further injury.
Sabathia finished the season with a flourish, allowing just a single run in three of his last four starts. In his final start this past Thursday against the Red Sox, Sabathia went 7 1/3 innings, giving up one run on four hits and two walks. He struck out eight and earned the decision in a 5-1 win.
Sabathia's 223 wins are second among active pitchers behind Mets right-hander Bartolo Colon, who has 233.
Barry M. Bloom is a national reporter for MLB.com and writes an MLBlog, Boomskie on Baseball. Follow @boomskie on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.