Bengals adding RBs?

The Cincinnati Bengals got a 1,000-yard season out of BenJarvus Green-Ellis in 2012 (1,094 yards, to be precise), and while that was an acceptable outcome, they'd like to bolster their RB corps heading into 2013, to establish more of a run-centered offense, according to Geoff Hobson of Bengals.com. So will they be players in free agency for the likes of Rashard Mendenhall, Ahmad Bradshaw or Reggie Bush?