A blog I've been enjoying lately is The Great American Reds Blog. For the past couple of weeks the owner of the site has been doing a very in depth position by position analysis of the NL Central. Here is what GARB has done so far and I encourage you to check it out:
Catchers
First Base
Second Base
Third Base
Shortstop
Left Field
Center Field
Right Field
Very good, very ambitious stuff. Make sure you've got a few minutes when you click those links, there's a lot of quality information to digest.