Counting stats are usually directly proportional to playing time.
Remember, i didn't say outright "Bucholz is the same or better pitcher than Vasquez". I stated (and clarified) that in a head-to-head matchup between both teams those two pitchers starting, they are likely to yield similar results.
Bucholz is an unknown quantity, but in the AL East, so is Vasquez, there's really no other way to look at it.
It's easy to look at his 2009 and think he'll dominate in '10, but when you put things in context and look at his AL track record (which is pretty significant) you'll see that even though he pitches a lot of innings, he's never been a "very good pitcher" in the AL, and with him being older and going to that launching pad, the outcome does not look pretty.