49ers’ Christian McCaffrey out vs. Rams, expected back for playoffs

Christian McCaffrey won’t play Sunday against the Los Angeles Rams, and neither will Ambry Thomas or Arik Armstead.

That was about as specific as coach Kyle Shanahan got Monday when discussing who will play and who won’t when the 49ers (12-4) host the Rams (9-7) in their regular-season finale having already wrapped up the No. 1 seed, a first-round bye and home-field advantage throughout the playoffs.

McCaffrey left in the second half with a calf injury, didn’t return, and called it “minor” in the post-game celebration after a 27-10 road win against the Washington Commanders.

“We’ll keep him out this week,” Shanahan said. He later added McCaffrey is expected to be full-go for the 49ers’ first playoff game following the bye.

“We’re real confident in that and it was good news,” Shanahan said. “Could have been a lot worse. “We’ll take care of him this week and hopefully he’ll get to go during our off week.”

McCaffrey finishes the regular season with a career high 1,459 yards rushing on 272 carries and should win his first rushing title given his 315-yard lead on the Rams’ Kyren Williams, who is No, 2 with 1,144 yards. With 67 receptions for 564 yards, McCaffrey’s 2,023 yards from scrimmage also lead the NFL as does his 21 touchdowns. It’s the second time he’s had more than 2,000 yards from scrimmage, with 2,392 yards in 2019 with Carolina.

The 49ers have not had an NFL rushing leader since Hall of Famer Joe Perry in 1953-54.

Thomas played with a cast protecting a fracture on his hand and will have surgery Tuesday. Shanahan said there was a chance Thomas could have played Sunday following the surgery if needed, although now he’ll most likely return the following week.

As for Armstead, who has missed the last four games with a foot injury, Shanahan said, “We’ll continue to rest him, get him ready for the playoffs.”

Wide receiver Jauan Jennings and tackle Jaylon Moore have both been in concussion protocol for the last two games and will be evaluated this week, as well as tight end Ross Dwelley, who has a high ankle sprain and may sit it out. The same goes for left guard Aaron Banks, who was active and available in case of emergency but didn’t play against Washington.

As far as resting healthy players, Shanahan said the 49ers were still in the process of working on a plan for the last game — and that includes starting quarterback Brock Purdy.

“We don’t have that plan yet,” Shanahan said. “We’re still discussing those things.”

Others who could either sit or get limited time include left tackle Trent Williams, tight end George Kittle and front-line defensive players such as edge rusher Nick Bosa.

“No one is set right now,” Shanahan said. “I’m still discussing that with coaches and trying to figure it all out, what’s best for us, and I’ll probably discuss it with those players also. Not as many as you might think. It’s a hard thing to do and it’s not always the best thing to do too. We’re going to take everything into account and it’s something we’ll continue talking about throughout the day tomorrow.”

Regardless, Shanahan wants to stay in the routine of practice and preparation.

“You’ve got to make sure you prepare for games by practicing and we’ve got a game on Sunday so when you give guys the game off, practice changes too, and that can end up hurting guys a lot,” Shanahan said. “You end up developing bad habits. I’ve seen it cost a lot of teams.”

The Rams have also clinched a spot in the playoffs and are currently the No. 6 seed. They could fall to No. 7 should they lose to the 49ers and Green Bay win its finale at home against Chicago.

THE FLIGHT HOME: With wrapping up the No. 1 seed coming as a surprise, the flight home was more jubilant than your standard cross-country flight.

Shanahan said he fell asleep for part of it, re-watched the game and then talked with players who were playing cards and enjoying themselves, although some were dozing off.

“It was pretty cool. The guys had a good time,” Shanahan said. “They worked real hard for that and I don’t think they expected to get it last night so it was a pleasant and I know the guys enjoyed it on the ride home.”

ELIJAH COMES THROUGH: The 49ers considered activating Elijah Mitchell for the Ravens game, but decided against it although his practice reps were getting stronger.

Mitchell, who has missed five games with a knee injury, hit the ground running as he’s done the previous two seasons. Mitchell has played 26 games and missed 25 since arriving as a sixth-round draft pick out of Louisiana. Mitchell had a season-high 80 yards on 17 carries after McCaffrey went out with a calf injury and helped the 49ers dominate the clock.

“When Elijah’s 100 percent he’ one of the better backs in this league,” Shanahan said. “He’s going to go in and run like he always does. It’s a skill set he’s always had since the first day he got here and when he’s good to go, he always looks like Elijah.”

JOSEPH-DAY’S DEBUT: Defensive tackle Sebastian Joseph-Day, signed by the 49ers after being released by the Los Angeles Chargers, played 11 snaps in his debut and could get more extended time against the Rams.

Joseph-Day, at 6-foot-4, 310 pounds, has been primarily a two-gap player with the Rams and Chargers but with the 49ers his role won’t be tying up blockers as much as penetrating.

“It was good to get him out there,” Shanahan said. “We definitely like the guy, like the player. We’re asking him to do some totally different stuff that are the opposite of what we do. To get him a half-practice where he can work on a couple of things and go out and play 11 plays, I was real impressed . . . I think he’ll get a little more playing time than that this weekend.”

SECOND-HALF DEFENSE: The 49ers shut out Washington in the second half after leading 13-10 at halftime, holding the Commanders to just 94 yards of offense and 63 passing yards.