THOUSAND OAKS, Calif. — Los Angeles Rams quarterback Matthew Stafford is in the concussion protocol, and coach Sean McVay is uncertain whether the Super Bowl winner will be ready to play Sunday against Arizona.

Stafford entered the protocol Tuesday afternoon after consultation with the Rams’ medical staff, the team announced Wednesday. The Rams believe Stafford’s condition resulted from action in last Sunday’s 16-13 loss at Tampa Bay, and the team decided to put him in the protocol after the usual weekly round of postgame health evaluations.

“Nobody wants to be out there more than Matthew Stafford,” McVay said. “Nobody is a greater competitor, tougher, that I’ve ever been around. However, it was in terms of some of the questions that were asked (to Stafford after the game) in terms of getting to this point.”

Stafford has been one of the NFL’s most durable quarterbacks for most of his professional career, but he has been sacked 28 times this season — just two fewer than in all 17 games last season — while playing behind a mostly terrible offensive line that has used eight different starting combinations in eight weeks of action. Stafford was sacked four times last weekend by the Buccaneers, who were credited with eight quarterback hits.

Stafford’s wife, Kelly, reacted to the news with a post on the Instagram account of her podcast.

“The head is not something to be messed with,” Kelly Stafford wrote. “And I hope as this sport develops so does the concern for head health and the research around it. And no, I’m not ok. I have every emotion running through me. Concerned, angry, sad, tired … all of them.”

John Wolford, a Rams backup since 2019, is likely to start against the Cardinals at SoFi Stadium if Stafford can’t go.

“(We’re) still anticipating and having the optimistic approach that there’s a possibility that (Stafford) will be ready to go,” McVay said. “John has been our backup, but the reality is we’ll take it a day at a time.”

Stafford has missed only eight games over the past 12 seasons, and all eight occurred in 2019 with Detroit because of a midseason back injury.

Stafford hasn’t yet missed any of his first 29 games with the Rams, including four playoff contests last year. After leading Los Angeles to a championship in his first season, he has passed for 1,928 yards and eight touchdowns with eight interceptions this season while completing a career-high 68.4% of his throws.

“You put the priority where it’s about the person first,” McVay said. “This is so important, but when you think about it in the big picture, it’s a temporary moment in time. He’s got a beautiful family, wife, four daughters, there’s a lot of other responsibilities that these guys have.”

Wolford has been on the Rams’ roster for four seasons, and he has served as the top backup to Jared Goff and to Stafford during the past three years. Wolford made his NFL debut by starting the final regular-season game of the 2020 season when Goff was sidelined by a broken thumb, and he led the Rams to an 18-7 victory.

“It was a big game,” Wolford said Wednesday. “Obviously, as an undrafted player, these games mean a lot. I was just glad we were able to get a win, get in the playoffs. But it was my first career start, and it was a good one, a good memory.”

Wolford then started the Rams’ playoff game at Seattle, but injured his neck in the first quarter. He played only in mop-up duty last season, and he has yet to play this year.

“John is a guy that when he’s been in these situations, he’s stepped in and done a really good job,” McVay said. “Wasn’t too long ago that he had to come in a game that we had to have to get into the playoffs, and he performed incredibly well.”

If the Rams have to roll with Wolford behind center as they attempt to prevent the season from slipping away, they say they’ll be confident.

“I saw (Wolford) a few times in Seattle, so we know what he’s capable of,” said Rams linebacker Bobby Wagner, who spent his first NFL decade with the Seahawks. “He came down and did a lot of great things against us when I was down there. We have confidence in him that if he has to, he’ll be able to step up and make plays.”

Los Angeles has lost four of its past five games to fall two games below .500 for the first time in McVay’s coaching career. The Rams’ offense is one of the NFL’s worst so far this season, with a nonexistent running game behind that patchwork offensive line and a pronounced lack of game-changing offensive talent behind All-Pro receiver Cooper Kupp.

It could get even worse: Starting left tackle Alaric Jackson and center Brian Allen skipped the Rams’ workout Wednesday to rest knee injuries, although McVay hopes both will play Sunday.

The Rams also designated interior offensive lineman Coleman Shelton to return to practice Wednesday after a five-week absence with a high ankle sprain. McVay said Shelton, who has started at right guard and center this season, is likely to rejoin the lineup immediately if he’s ready.

Rookie running back Kyren Williams is expected to make his NFL debut Sunday if he stays on course in his recovery from an ankle injury. The Notre Dame product was designated to return from injured reserve on Oct. 26.