I think the answer here is Frank Smith. He knows the system and has been exposed to many systems since leaving the Saints. He currently is the nonplaycalling OC of one of the best offenses in the league working for one of the best offensive minds in the league so he can add to and freshen up up the offense. He's the kindof guy that could take a promotion to playcalling OC and PC could stay on in some reduced capacity to help Smith with the day to day OC responsibilities allowing Smith to be playcaller.