Coach Kyle Shanahan said Monday that Mostert has given the 49ers "no choice" but to use him as the leader of the team's backfield, Eric Branch of the San Francisco Chronicle reports.
Mostert first emerged in the lead role Week 13 at Baltimore, taking 21 touches for 154 yards and a touchdown while playing 74 percent of offensive snaps. Matt Breida's return from an ankle injury for Week 14 in New Orleans added some competition, but that didn't stop Mostert from getting a team-high 12 touches (for 109 yards and two scores) on 60 percent snap share. While Tevin Coleman may still be the nominal starter, Mostert is the best bet to lead the 49ers in carries and backfield snaps during a Week 15 home game against the Falcons.