If there's one thing we've learned about Francona, it's that he loves his veterans. Do you seriously believe that Schilling wouldn't be placed into the rotation if he was cleared to pitch?
Oh, and remember what happened last time Schilling came out of the bullpen? It's not where he's meant to pitch. Francona will place him in the rotation if he's capable of pitching, if not only for the fact that he's a veteran.
Should Schilling come back into the rotation? Only if there is a starter who's struggling after Colon has been given a shot.