Los Angeles Rams wide receiver Puka Nacua is expected to be placed on injured reserve after an MRI on Monday revealed sprains to the medial and posterior collateral ligaments in his right knee, along with turf toe.

Head coach Sean McVay confirmed the diagnosis on Monday and said the Rams expect to move Nacua to injured reserve, which carries a minimum absence of four games. McVay said the star receiver would be out for at least a month.

How the injury happened

Nacua was hurt on the Rams' final offensive snap of Sunday's 20-13 win over the Washington Commanders at Northwest Stadium. He took a jet sweep in the closing minute and was tackled hard, then walked off the field wearing a brace on his right knee.

The injury came at the end of a huge performance. Nacua finished the game with 14 catches for 150 yards and one touchdown, including the game-winning score when he leapt over Commanders cornerback Trey Amos in the back corner of the end zone to give the Rams a 20-13 lead.

McVay admitted he was second-guessing the decision to run the play with the game already in hand, a call that has now cost Los Angeles its best offensive weapon for at least a month.

What the MRI showed

The MRI found sprains to the MCL and PCL in Nacua's right knee, plus turf toe. The positive news for the Rams is that the scan did not show a torn ACL, which the team had feared could end his season.

ESPN's Adam Schefter and NFL Network's Mike Garafolo had reported on Sunday that the team did not believe Nacua had suffered a torn ACL, and Monday's imaging confirmed the ligaments are sprained rather than torn.

How long Nacua will be out

A player placed on injured reserve must miss a minimum of four games, and the Rams' Week 11 bye does not count towards that total. That means Nacua will sit out at least the trip to the Arizona Cardinals, the home game against the Green Bay Packers on Thanksgiving Eve, the home game against the Kansas City Chiefs and the road trip to the San Francisco 49ers on 13 December.

The earliest he could return is the home game against the Dallas Cowboys on 20 December.

A big blow for the Rams

The timing could hardly be worse for Los Angeles. The win over Washington was the Rams' third in a row and moved them to 5-4, above .500 for the first time this season, with Myles Garrett also starring on his return from knee surgery with three sacks.

But the receiving room is suddenly thin. Veteran Davante Adams is already sidelined with a hamstring injury, and with the trade deadline falling on Tuesday, the Rams may now have to look for short-term help at receiver.

Nacua had been the focal point of the Rams' passing game, catching 14 of his team-high 19 targets from Matthew Stafford on Sunday. Stafford completed 26 of 43 passes for 228 yards, a touchdown and an interception in the win.