Let me preface this by saying I'm not arguing for this to happen, just voicing another option. Feel free to bash vociferously. So, there's a lot of talk about moving Cully to safety, and I understand that completely because he played safety in college so it's not difficult to connect the dots. However, (and I'm not necessarily espousing this idea, but I think it might be worth thinking about) should we not also be considering moving Rogers to FS? He is just a few pounds lighter than Cully, a very willing tackler for a DB and he would be an upgrade in pass coverage. Also, he wouldn't be as exposed for his declining short area quickness. I think Harbaugh and Fangio want to get the best players on the field and playing. I think Cully is a better CB than Rogers at this point in their careers, especially given Rogers' declining value in the slot, and I'd like to see Cully continue his growth as a CB. Also, this idea is totally dependent on Asomugha being at least capable of being at least a solid third CB, and Brown being a capable slot-corner.
In this scenario I would envision the secondary something like this:
Rogers and Whitner manning the back end
Brown as the RCB
Cully and Nnamdi compete for LCB
In Nickel situations Brown slides into the slot and whoever loses the competition for the other starter's position (be it Nnamdi or Cully) comes in at RCB.
Pros: Gets our top 4 cover guys significant playing time. Doesn't stunt Culliver's growth as a top-flight cover corner. Potentially an upgrade in coverage at the FS position.
Cons: Rogers has no experience at FS (clearly a huge deal). Does he have the requisite skill set? Can he make the transition? Will he be willing to make the transition?