At least for 2005, anyway. Dave confirms.
We've known for a while that there was something structurally wrong with the guy - chalk this one up as another example of the failed approach of "rest & rehabilitation" (be wary of Guardado). I don't think anyone was really counting on Blackley being a major contributor at any level this year, so the news doesn't really effect the organization performance-wise in the short term, but labrum surgery is a big deal, and the team seems to have a proclivity for this kind of thing.
Funny note from a Finnigan article last September:
Tendinitis, as you may or may not know, is medical lingo for "something's wrong with you, but I don't know what it is, so here's a fancy word to make both of us more comfortable."