The former USC tailback signed a one-year contract with the
Four former Trojans are on the 49ers' active and reserve-future rosters, including center Marcus Martin, cornerback
Bush was released in February by the
He was slowed in 2014 because of an ankle injury. In 11 games, he rushed for 297 yards and two touchdowns in 76 carries. He also caught 40 passes for 253 yards.