Raheem Mostert has High-Ankle Sprain, Likely Headed to IR

The 49ers run game just took a major hit.

The 49ers run game just took a major hit.

Running back Raheem Mostert has a high-ankle sprain and will miss the next few weeks, per head coach Kyle Shanahan, who said Mostert likely will go to the Injured Reserve list.

To make matters worse, center Ben Garland likely will go to IR with a calf strain. And Garland was filling in for starter Weston Richburg, who’s been on the PUP list all season and won’t return until Week 12 at the earliest. Meaning the 49ers will be down to their third-string center -- Hroniss Grassu.

But Mostert is the bigger loss.

Mostert is the best running back on the 49ers and the engine of their offense. He injured his ankle Sunday night against the Los Angeles Rams and carried the ball just once in the second half before leaving the game. Jerick McKinnon and rookie JaMycal Hasty replaced Mostert in the 49ers backfield.

“Hopefully Jeff Wilson Jr. returns this week,” Shanahan said on Monday. “He had a tight calf last week, so hopefully he’ll be good to go on Wednesday. Tevin Coleman will be a long shot. I know he’s eligible to come back this week. Have a feeling it will be another week.”

While Mostert is out, Hasty could see his role increase drastically. He showed tremendous quickness and explosion in the second half against the Rams, and finished the game with 9 carries for 37 yards.

“The moment wasn’t too big for him,” Shanahan said. “We like to keep our guys fresh. Once we lost Raheem, Jerick had been going for a while. It was the perfect time to change the pace and bring in a fresh guy. He was the guy that we had left, and he came in and was ready for the occasion. He gave us a little bit of a spark and helped us out.”