49ers RB Jarryd Hayne will step into backup role Sunday

With news of Reggie Bush (calf) being ruled out Sunday, 49ers running back Jarryd Hayne will be Carlos Hyde's primary backup, CSN Bay Area reports.

Hayne stepped into the backup role when Bush went down Monday against the Vikings and he will serve the same role Sunday. It is unclear whether he will return punts or not, but he should see anywhere from 5-10 touches against the Steelers.