On the MLB on XM show this morning there was a lengthy discussion of Manager of the Year in the NL so far, it came down to either Davey or Mattingly. While I'm obviously biased, I think you'd have to give it to Davey given the injuries and the tougher competition in the NL East.
I'd actually say that Mattingly has done a lot better job than Davey this year. DJ's done really, mind you, but Mattingly does not have the starting rotation Davey does and has had just as many if not more injuries, including Kemp.