The 49ers elevated McNichols from their practice squad Saturday ahead of Sunday's Week 15 game against Arizona.
McNichols was elevated to the active roster for the first time this season last week. He didn't log any offensive snaps but did play on six special-teams snaps against Seattle. McNichols should provide depth at running back Sunday due to Elijah Mitchell (knee) being ruled out, but the former is unlikely to see much (if any) action on offense.