Mason (hamstring) was active in Saturday's 37-20 win over the Commanders, but he did not receive a carry and logged snaps only on special teams.
Mason's hamstring tightened up during practice this week, but he was ultimately cleared before kickoff. Fellow rookie Tyrion Davis-Price -- who was a healthy scratch for the last two weeks -- took over the backup duties behind Christian McCaffrey and finished with 30 yards on nine carries. Perhaps the decision to limit Mason to special teams was a direct result of him missing practice this week due to injury. The Georgia Tech product was excelling at spelling McCaffrey prior to this unexpected shakeup, so it wouldn't be surprising to see him reclaim that role against the Raiders on Jan. 1.