The San Francisco 49ers are expected to be without Raheem Mostert for the remainder of the season after he suffered a broken right forearm against the Oakland Raiders on Thursday night.

Kyle Shanahan said he wasn't told whether Mostert was done for the year, but added, "I would assume so with a broken arm."

Mostert took a handoff to the left side and was taken down for no gain by defensive tackle Clinton McDonald with 4:38 to go in the third quarter. Before the injury, Mostert had rushed for 86 yards in seven carries, including a 52-yard touchdown.