PHOENIX -- Arizona has placed Chris Johnson on the injured reserve/designated to return list, a move that means the only way the running back will play again this season is if the Cardinals reach the Super Bowl.
A person with knowledge of the situation said Tuesday that Johnson chipped or fractured his tibia where it meets his left knee. The person spoke on condition of anonymity because the team has not revealed details of the injury.
Coach Bruce Arians said on Monday that Johnson was hurt when he took a helmet to the knee in Sunday's 19-13 victory at San Francisco.