The probowl is a meaningless designation. Like hookem said, and a few more..
Elvis Grbac made the pro bowl.
Kordell Stewart made the pro bowl.
Kerry Collins made the pro bowl.
Derek Anderson (yes, the Cleveland Browns QB) made the pro bowl.
Read that list out loud and tell me that that's the measuring stick you want to use for success.
Stats do not in fact tell the whole story, but they're a completely reasonable piece of it, far more so than the pro bowl..
and his stats stink, just like those 'pro bowlers'.