I think you can swing Encarncion later on in the year for some more OF help.
I'd keep Zimmerman since he will be a killer in avg and you seem to have a good amount of HRs with Blalock, pujols, Wilson, etc.
I agree with Intense about the Catcher position.
Make sure to stay on top of Mota, and Putz if they are still available. I'm guessing all of the other closers are gone, but even a Weathers or Orvella may be better than Wickman.