Bonser likely out for the 2009 season

The Twins will likely be without pitcher Boof Bonser for the entire 2009 season after doctors discovered partial tears in the labrum and rotator cuff in his right shoulder during arthroscopic surgery on Wednesday.

Two previous MRIs done on Bonser's shoulder had revealed no structural damage. But the tears were discovered and repaired during the arthroscopic scope performed by Rays orthopedist Dr. Koko Eaton.

Bonser is expected to miss six to eight months recovering from the surgery.

The pitcher first began experiencing shoulder discomfort at the end of last season. An MRI performed at that time revealed no structural damage, and Bonser was ordered to rest the shoulder and begin a rehabilitation program.

But the rehab didn't help. Bonser tried to throw in early January and felt the same discomfort. The right-hander received a cortisone shot from Dr. Eaton just a few days before he reported for Spring Training, The shot had little effect on the problem, and Bonser has not really thrown since workouts began last Monday.

With Bonser out of the mix for the Twins bullpen, right-handers Philip Humber, who is out of options and Jason Jones, a Rule 5 pick, are now the favorites to win the final spot if the Twins keep seven relievers. R.A. Dickey, a knuckleballer, and left-hander Sean Henn are also among those expected to compete for the job. 

There is a chance that the Twins could break camp with an 11-man pitching staff, meaning just six relievers will make the Opening Day roster, but so far that appears to be a long shot.