Bush is still recovering from the left calf injury that he suffered on Monday against the Minnesota Vikings. He was injured during the first quarter of that game and, after struggling to get off the field, was eventually carted to the locker room.
On Tuesday, he had an MRI at Stanford which revealed that there was no tear involved. While he is currently walking without a limp, Bush is receiving electro-stimulation therapy to the calf.
Jarryd Hayne will serve as Carlos Hyde's backup on Sunday. Mike Davis will be activated for the game as well.
WR Bruce Ellington has an ankle injury and his status for Sunday is unknown. However, he has been able to practice with the team.