The 49ers signed Vaughn to the practice squad Tuesday, David Lombardi of SFStandard.com reports.
Vaughn was let go from the 49ers' practice squad Nov. 12, but he has been brought back following injuries to Christian McCaffrey (knee) and Jordan Mason (ankle) during San Francisco's Week 13 loss to Buffalo this past Sunday. Vaughn could be elevated to the active roster if the 49ers need depth at running back behind rookie Isaac Guerendo and Israel Abanikanda.