Peavy is a great competitor and has dazzling "stuff". However, I think he tires himself out early on in games. He rarely pitches deep into the later innings.
Sometimes it looks like Peavy is tired even in the 2-3rd inning. He complained earlier in the year of "dead arm" so its a little bit of a concern. All of this being said, when Peavy is healthy and rested, he is almost unhittable(see the dodger game).
I traded him in one of my leagues just before his latest 7 run implosion. I don't expect him to pitch like that the entire second half, but don't be suprised if you see outings like that from him every once in a while....But also know that somedays you'll get a start like this 8 IP, 0 ER, 13 SO