Boston Red Sox reliever Joel Hanrahan will undergo season-ending surgery next week to repair a damaged flexor tendon in his throwing arm.

The surgery requires about six to nine months of recovery time. If additional ligament damage is discovered, Tommy John surgery may be required as well.

"[Dr. James Andrews] basically walked in, looked at my arm, touched it, and said there really wasn't a decision," Hanrahan said. "The flexor pretty much tore right off the bone. It wasn't really a decision. It's just a matter of what kind of surgery it was going to be. As of now, it's just going to be the flexor. When he gets in there and takes a look, it could be worse, [or] it could be not as bad."

Hanrahan was 4-for-6 in save opportunities for the Red Sox while walking six batters in 7 1/3 innings and accumulating a 9.82 ERA.