Mostert is in line to play in Sunday's preseason contest at the Chargers, David Lombardi of The Athletic reports.
Coach Kyle Shanahan said after Friday's joint practice with the Chargers that 49ers starters will log "a quarter, a quarter and a half" in their second exhibition. As a result, it appears San Fran is set to have its dress rehearsal for the regular season Sunday. Mostert should get a lot of the backfield reps while the starters are on the field, yielding the occasional touch to Trey Sermon and perhaps even Wayne Gallman.