Kurt Ainsworth isn't going to retire. He's out for the 2005 season, but he plans on rehabbing and making a charge to get back into the game in '06.
Ainsworth is now something of a major project with this latest injury. He will have basically not pitched since 2002 by the time he gets back - 15 appearances overall in '03 (split between Fresno, the Giants and the O's), three in '04 between Aberdeen and Baltimore, and none this year except a couple rough spring outings.
Ainsworth will be 27 by next spring (his birthday is in September). At 28, Jaret Wright made himself relevant within the baseball world again after four seasons of injuries. Wright was a better prospect than Ainsworth, but Ainsworth was not a slouch in potential either. Do I expect Ainsworth to have a 15-8, 3.28/1.28 season next year? It'd be pretty optimistic. Wright's turnaround, be it Mythical Mazzone Magic or just plain finally staying healthy long enough to do anything positive, was a pretty big rarity.
Either way, Ainsworth will try to make it back, and that's great. Wish him good luck and good health, because he definitely needs the latter and may well need the former.