One way of examining this disparity is by looking at the number of runs given to a pitcher after he has left the game and adjusting it to show how many runs he should have given up. The Baseball-Reference.com Starting Pitching Page has a record for each starter's bequeathed runners as well as how many of those runners scored. Overall in 2011, starters left the game with 3186 runners on base and 1046 of those ended up scoring. In other words, on average, 33% of the runners left on base when a starter left a game ended up scoring.
Taking this data into account, some pitchers clearly need to thank their bullpens for helping them out and allowing only a minimal amount of their runs to score, while other pitchers probably have some less than gracious feelings toward their relievers.
First, the pitchers who benefited the most from the help of their bullpens.
And the pitchers who were hurt the most:
Of course there are other factors that need to be considered, as well. Certainly the base positions of the bequeathed runners is a key piece information. If a pitcher leaves runners primarily on third instead of on first, his bullpen will naturally let more runners score.
Nevertheless, it interesting to ponder, particularly given the accolades that the 11th pitcher in the top list has received. Would a jump in ERA from 2.40 to 2.53 mean a lot in how people view Verlander? Probably not. But it is still interesting to think about.