Mason (hamstring) was a limited participant at Wednesday's practice, Eric Branch of the San Francisco Chronicle reports.
After his hamstring tightened up on him last Wednesday, Mason was limited last Thursday before going down as questionable ahead of Saturday's game against the Commanders. He ended up suiting up for the Week 16 game, but he also was contained to 17 snaps on special teams, as Tyrion Davis-Price handled the running-back reps that didn't go to Christian McCaffrey. There's a chance Mason takes over the No. 2 role out of the 49ers backfield Sunday at Las Vegas, but he may have to get back to a full session before the end of Week 17 prep in order to do so.