Oakland Raiders quarterback Carson Palmer left Sunday's game against the Carolina Panthers in the first half with a rib injury after taking a hard hit to his back from defensive end Greg Hardy.
Palmer was taken to the locker room. X-rays taken were negative, according to the CBS TV broadcast, but was later ruled out from returning.
Hardy was penalized for unnecessary roughness for leading with his helmet to Palmer's lower back.
Palmer was replaced by Matt Leinart.