For what it's worth, last year after becoming a starter (or bulk guy in one instance) full-time in June, he pitched 91 2/3 IP. Of those innings, they were exactly split between opponents who were (in my opinion) still in contention and those who weren't (including two starts against the A's and one against each of Boston, Baltimore, Kansas City, Detroit, Minnesota, and Texas). In the starts against the non-contenders, he had a 2.17 ERA. Against the contenders, his ERA was 4.92.
(Standard caveats about sample sizes apply here, obviously...Just thought it was interesting that those start/bulk appearances coincidentally ended up being the exact same in terms of innings pitched...)