The Christian McCaffrey trade fundamentally changed the ceiling for the 49ers’ offense last season. For the first time since he was acquired, the 49ers face the prospect of him missing time.

McCaffrey suffered an oblique injury on Sunday, and after attempting to return to the game early in the second half, he returned to the locker room and was deemed out.

Kyle Shanahan provided updates on McCaffrey, Deebo Samuel, Trent Williams and others on Monday, with the running back’s status the most murky.

At the time of Shanahan’s call, McCaffrey was still undergoing MRIs on what Shanahan called an oblique/rib injury, “but hopefully not both.”

If McCaffrey does miss time, Shanahan gave the nod to Elijah Mitchell over Jordan Mason. Mitchell has missed 12 games in the regular season last year and three this year so far, and was out-worked by Mason on Sunday. Despite that lack of availability, he sounds to be the favored No. 2 option.

I mean, Elijah has earned a ton with us over these years. I think Elijah, when he’s been healthy, has been as good of a back as there is. He’s had a hard time staying healthy, but I also can’t take away anything from JP. I mean, every time JP’s got his opportunities, you guys see how he’s done. So both of those guys have done very well. Elijah came back and practiced late last week on Thursday, so he only got really one true day of practice in and that’s why JP got the first nod once Christian came out, but we’ve got two really good players there, And I know Ty Davis-Price is waiting for his opportunity also. So hopefully Christian will be good to go this week, but if not, we’ve got a group of backs we can rely on.

McCaffrey was the only one not given a general time frame, while three others were designated as day-to-day:

• Deebo Samuel (shoulder) was injured on the first play of the game, in what Shanahan described as a pinpoint hit that took feeling out of his left arm.

“He just took a shot on the shoulder,” Shanahan said. “It wasn’t overly big or anything, it just connected right. If you watched him the next eight plays, you could just tell the feeling was starting to go because he couldn’t use his left arm. Tried to come back, but just couldn’t get feeling back in it, so we had to shut him down.”

• Trent Williams (ankle) sprained his ankle, but avoided a high ankle sprain. Shanahan credited the fact that he played through the injury against Myles Garrett, who got the better of him, calling it a “pretty courageous effort.”
• George Odum (thigh) suffered a quad contusion.

In other injury news, Dre Greenlaw (hamstring), who missed Sunday’s game, is expected back at practice this week, which is an encouraging sign for Monday night’s matchup with the Minnesota Vikings.

While there wasn’t a concrete update on rookie corner Darrell Luter Jr., who has been on the physically unable to perform list since the start of training camp with a bone bruise in his knee, Shanahan said he should be on pace to return soon, assuming the 49ers need his help.