Hmm...Seems like you got a little bit of everything.
Lets start out with the catcher position...Lo Duca and Lopez should do fine (especially Lopez, cause it's the last year of his contract in ATL).
1B Durazo is kinda weak and might spend a lot of time on the DL. So that needs improving...
2B Bellhorn isn't too bad, but he ain't too good either (lets agree on Average).
3B Aramis Ramirez is horrible!!! He had an off year last year and I frankly don't think he's gonna rebound. (Hit me if I'm wrong
SS Rich Aurillia should be fine. He also had an off year last year. But in comparison to Ramirez, I think he'll be back in shape. Your Outfield is fine!
Lets go on to the pitching staff:
You might wanna get another decent starter and reliable closer. Otherwise it's fine.
I hope this was of any help to you. Good luck!