It's understandable that lots of folks are nervous about players like Pedro or Randy Johnson. If you own one of them in your league, you're bound to have a substantial investment, be it an early pick or a large chunk of your budget, tied up in a single player, and an injury could be disastrous.
Still, there's no real way to predict injuries, even if attempts with stress index ratings and the like are somewhat popular now. Watching pitch counts, keeping track of injury histories, etc. is important, obviously, but it seems to me that if the medical staff of the teams involved thinks a player can play without significant injury risk (and they certainly don't want to lose their team's investment, either), that opinion carries far more weight than that of fantasy pundits...
If you truly want to minimize the risk of injury on your team, the best way is still to spread that risk around, for instance by buying three $15 players instead of Pedro at $45. The more baskets you have, the less eggs can break.
Anyway, here's hoping Pedro remains healthy and continues to pitch at a level few others are capable of!