Mostert (knee) is active for Sunday's game against the Dolphins.
Mostert is making his first appearance since Week 2 after being limited in practice Wednesday through Friday. Per Jennifer Lee Chan of NBC Sports Bay Area, Mostert was wearing a compression tight on his right leg during a pregame warmup, which seemingly will be supporting the knee that endeared a sprain three games ago. Mostert's workload may be limited as a result as he'll have to contend with Jerick McKinnon, Jeff Wilson and perhaps JaMycal Hasty for reps out of the 49ers backfield.