Cardinals keep Rashad Johnson

The Cardinals have signed safety Rashad Johnson to a three-year deal, NFL Network’s Ian Rapoport reported Monday night. Johnson, 27, is entering his fifth NFL season. He was slated to become an unrestricted free agent on Tuesday. The 5-11, 204-pound Alabama product has appeared in 57 games (14 starts), notching 133 tackles, defending 10 passes…