The Athletics’ Dallas Braden, who threw a perfect game in 2010, made three starts this season, posting a 1-1 record and 3.00 ERA, before his left shoulder began giving him trouble. The A’s first said he needed rest and there was “no structural damage”, but after a few throwing sessions, Braden suffered a setback, and Monday he underwent surgery. The surgery was performed by Mets doctor David Altchek.

Today, via tweet from John Shea, the San Francisco Chronicle’s national baseball writer, we learn that Braden is expected to miss the rest of the 2011 season.

So far, the A’s starting pitching has held up in Braden’s absence; Tyson Ross has made five starts in his place and posted a 3-2 record, a 2.32 ERA and allowed only one home run in 31 innings. The 24-year-old righthanded Ross may have to keep up this performance if the A’s, currently at 21-20, are to have any hope of contending in the AL West.