Los Angeles Rams quarterback Matthew Stafford has entered the concussion protocol putting him in doubt for Sunday's game against the Arizona Cardinals.

Rams head coach Sean McVay confirmed on Wednesday that Stafford had entered the protocol on Tuesday with medical staff performing their "cleanup after the game" from Sunday's 16-13 loss to the Tampa Bay Buccaneers.

Stafford has not missed an NFL game since 2019, but if he is unavailable, John Wolford would be the Rams' starting quarterback.

"We'll take it a day at a time with him," McVay told reporters. "We're still anticipating and having the optimistic approach that there's a possibility that he'll be ready to go."

McVay added: "I know Matthew's going to do everything in his power to try to be able to be ready and we'll just take it a day at a time.

"But John's a guy that when he's been in these situations, he's stepped in and done a really good job. And it wasn't too long ago that he had to come in a game that we had to have to be able to get into the playoffs and he performed incredibly well."

McVay clarified that Stafford had not shown any indication that he was dealing with concussion symptoms during Sunday's game. He said medical staff "determined that they felt like that [entering protocols] was the best thing for him".

Stafford completed 13 of 27 passes for 165 yards and one touchdown with no interceptions against the Bucs. He was sacked four times in the game.

The 34-year-old Super Bowl LVI champion has a 68.4 per cent completion rate for 1,928 passing yards with eight touchdowns and eight interceptions this season.

The Rams are 3-5 and third in the NFC West, while the Cardinals are 3-6 and fourth in that division.