After being examined by Mariners medical director Edward Khalfayan, Dr. Lewis Yocum and Dr. David Altcheck, all three agreed that the third surgery in three years is needed.
Khalfayan and Yocum will perform the latest surgery.
Bedard, 31, had surgery on his left (pitching) shoulder on Aug. 14, 2009, to repair a torn labrum. He has spent the 2010 season rehabilitating following the surgery. Yocum performed the surgery in Los Angeles, Calif.
Despite periods of optimism during his rehabilitation this year, he was unable to make it beyond a rehabilitation assignment at Triple-A Tacoma.