Mostert (knee), who is listed as questionable for Thursday's game against the Cardinals, is in line to play, Adam Schefter of ESPN reports.
Mostert's availability will be confirmed approximately 90 minutes before the 8:20 p.m. ET kickoff, when the 49ers will unveil their inactive list. With Matt Breida (ankle) also on track to play, Mostert will likely serve as the No. 3 option in the 49ers' ground game.