Right-handed pitcher Ben Sheets underwent surgery on the flexor tendon in his right elbow on Monday, and Oakland A’s manager Bob Geren said the procedure was more extensive than anticipated.

According to the Bay Area News Group (via the Countra Costa Times), in addition to fixing the tear in the flexor tendor, Dallas-based orthopedist Dr. Keith Meister repared damage to the pronator tendon and ulnar collateral ligament. It’s unknown what the timetable for recovery is, but in a media conference call two weeks ago, Sheets said he wasn’t sure if his elbow would recover enough for him to ever pitch again.

It is possible that Sheets may try to force a comeback. He is one year short from his full Major League pension from vesting. He currently has nine years of service time.

Sheets, 32, was 4-9 with a 4.53 ERA in 20 starts for the A’s this season. Sheets drew interest from multiple teams before the July 31st trade deadline, but his injury derailed any opportunity for the A’s to trade him.