Though we haven't noticed nor been notified either way, Bengals running back Brian Leonard is out of the game and standing on the sidelines in street clothes, according to Dan Hoard and Dave Lapham on the Bengals Radio Network (first I heard of it).
Dave Lapham said that while talking with teammates, he was pointing to his left hip. Eventually the Bengals announced that Brian Leonard is out with a rib injury.
That leaves BenJarvus Green-Ellis and Cedric Peerman as the team's lone running backs, not including fullback Chris Pressley.