Greinke

And in the American League?

Still Greinke. Obviously. The only pitcher within half a run of his ERA is King Felix; the only other pitcher to consider is Roy Halladay.

Halladay is my #2 and Hernandez is #3. Halladay's thrown nine (!) complete games this year; Hernandez has 2. I think complete games matter. These days, it's rare to give the entire bullpen a day off. Halladay also leads all baseball in shutouts (4) and innings. He's your Cy Young award winner, if Greinke didn't come out of nowhere this year to dominate like he did.