Mostert carried the ball 12 times for a team-high 79 yards in Sunday's 24-20 win over the Steelers.
He also failed to catch his only target. Mostert's 230 scrimmage yards over the last two games are impressive, but they may not guarantee him a significant role in the Niners' backfield moving forward. The team gets an early bye in Week 4, which could give Tevin Coleman (ankle) the time he needs to get back in game shape, and Jeff Wilson's emergence as a goal-line specialist could leave Mostert as the odd man out in the team's backfield committee once Coleman returns.