Mostert (ankle) has been ruled out for the rest of Sunday's game against the Rams.
Mostert appeared to tweak his ankle on a catch late in the first half, and he was ruled out in the third quarter, leaving Jerick McKinnon to operate as San Francisco's lead back for the rest of the contest. This is the latest injury setback for Mostert, who returned from a knee injury last week. Mostert was busy prior to exiting, with 17 carries for 65 yards and two catches for 11 yards. After the game, coach Kyle Shanahan said Mostert tried to come back into the game but checked back out after one play.