MRI's of the shoulder aren't terribly accurate. The shoulder is a tight joint, surrounded by a lot of muscle mass. It is not unusual for doctors to interpret MRI as showing one thing, only to find something more, or less, serious during surgery. I was told, by the surgeon who did my son's surgery, that clinical exam is more specific for labrum issues than MRI. FWIW, during surgery they also discovered a small rotator cuff tear that had not shown up on MRI.