Bush was carted off the field Sunday at St. Louis, Cam Inman of the San Jose Mercury News reports. The 49ers reported that Bush is questionable to return with a knee injury.
Getting the start for Carlos Hyde (foot), Bush slipped on the concrete near the padded wall on a first-quarter punt return. Bush remained on the ground for some time before a cart was called to take the running back to the locker room. In his absence, Mike Davis should receive the bulk of the carries.