Here are the rankings of all 185 pitchers with more than 5 starts this season, ranked by VORP.
If you stratify each group of 30 into a starter tier, we have
Lannan #1
Perez and Redding #3
Bergmann #4
Then,
Chico and Hill below #5.
Clippard, Mock and Balester don't have meaningful sample sizes, though Clippard and Balester are slightly positive, Mock slightly negative VORP.