I wouldn't be surprised if it was one of the extra DB's (likely Hudson or Taylor...Taylor could replace Sheets on the PS should Sheets get the call).
The only issue with Sheets coming up to the roster is that if he fares well it may be hard to get him back on to the PS should need be later on (like another injury and a need for a roster spot comes up). Also Sheets may have a hard time making the active roster once Gore comes back if we keep him on the 53.
Should we go the way of the vet FA Warrick Dunn may be a smart option. He proved last year that he had still had something in the gas tank.