The 49ers running back was shoved out of bounds on a punt return and failed to slow down before reaching the Edward Jones Dome’s concrete perimeter. He slipped, fell and immediately grabbed his knee.
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San Francisco announced Bush, who was carted to the locker room, was questionable to return. NFL Network’s Ian Rapaport later reported the extent of the damage: An ACL tear, pending MRI results.
Bush, 30, signed with the 49ers in March after stints with the Saints, Dolphins and Lions. He has rushed for 28 yards on eight carries in four games this season and has picked up another 19 yards on four catches.
Bush on Sunday made his first start of the season in place of injured Carlos Hyde. Mike Davis replaced Bush in the lineup.
Bush, a nine-year veteran, has a history of injuries, including left knee issues early in his career.
