Mostert (ankle) isn't participating in Thursday's practice, Cam Inman of The San Jose Mercury News reports.
Mostert's absence from practice for the second day in a row comes as little surprise after coach Kyle Shanahan admitted earlier this week that Mostert will likely be forced to injured reserve due to the left high-ankle sprain he sustained in the 49ers' Week 6 win over the Rams. Jerick McKinnon (32 percent snap share) and JaMycal Hasty (21 percent) saw the majority of the backfield reps after Mostert went down with the injury, suggesting Shanahan could be leaning toward a committee approach at the position while the top option is sidelined. McKinnon had previously taken on a three-down role when Mostert was sidelined for a pair of games earlier in the season.