49ers RB Mostert says he’ll undergo surgery

LEWISBURG, W.Va. — Raheem Mostert won’t be returning this 49ers season, after all. There’s no assurance he’ll be back with them next year, either.

Mostert tweeted on Tuesday that his upcoming knee surgery will be of the season-ending variety to repair torn cartilage. He got injured four plays (and two runs) into Sunday’s opening win over the Detroit Lions.

With his contract expiring after this season, Mostert decided a more extensive surgery will enhance his chances of coming back stronger next year, wherever that may be. Coach Kyle Shanahan said Monday the 49ers hoped Mostert could return in two months.

“Faithful, after consulting with multiple doctors and weighing my options, I will have season-ending surgery to repair my knee,” Mostert tweeted just before 3 p.m. ET, as the 49ers bunker in at The Greenbrier Resort for this week’s practices ahead of Sunday’s game at Philadelphia.

“This gives me, without a doubt in my mind, the best possibility at coming back 110%. I have ALWAYS come back stronger and will this time too! I have faith in myself, my doctors, my support system, my team and God. He makes no mistakes!!

“I’m gutted. This sucks! This is obviously not what I worked so hard for. I wish more than anything I could be out there on the field with my brothers!!!

“Thank you for your support in our decision. I’M FAR FROM DONE! — Mosterati”

ran for 104 yards upon Mostert’s exit, and he is in line to start against the Eagles. Other backfield options are second-year back JaMychal Hasty and rookie Trey Sermon, the latter having been a healthy scratch Sunday.