McCourty is a better safety than both Chung and Gregory. Perhaps our best lineup when they return is to keep McCourty at safety with Chung, Gregory comes in to replace McCourty on dime situations, move McCourty to corner with Dennard with cole in the slot and moore in there as well.  

I don't know,just speculating..but it seems the pats secondary plays better in man coverage with Chung and Gregory on the bench.