Bush left the field during the first quarter and was eventually carted to the locker room. He had an MRI performed on Monday at Stanford and remains week-to-week. The calf strain is not believed to be serious and there was no tear involved.
San Francisco 49ers
Questionable: RB Reggie Bush (calf)
Pittsburgh Steelers
Questionable: CB Cortez Allen (knee), CB Brandon Boykin (groin), LB Ryan Shazier (knee)
Probable: S Will Allen (concussion), QB Landry Jones (concussion), S Mike Mitchell (hip), LB Sean Spence (hamstring)