Lindsey Thiry ESPN 2 Minute Read

THOUSAND OAKS, Calif. -- Los Angeles Rams receiver Cooper Kupp suffered a knee sprain Sunday and could be sidelined for this week's game against the San Francisco 49ers, coach Sean McVay said.

"Most likely he probably will miss this game," McVay said Monday. "And then dependent on how he responds it will just kind of be on a week-to-week basis."

Kupp was carted off the field in the first half of the Rams' victory over the Denver Broncos after safety Darian Stewart brought him down with a horse-collar tackle.

McVay said he initially thought the injury appeared as though it could have been season-ending.

After evaluation, Kupp started the second half but played only one series after the training staff determined it was in his best interest to sit out.

Receiver Josh Reynolds was inserted in Kupp's absence as Robert Woods, for a second consecutive week, shifted to play Kupp's position after he was sidelined.

With Kupp's injury, the Rams are down to four healthy receivers, including Woods, Reynolds, Brandin Cooks and KhaDarel Hodge.

Backups Pharoh Cooper and Michael Thomas are on injured reserve after suffering an ankle and groin injury, respectively, in Week 1.

McVay said the team was exploring the possibility of adding another receiver.

"There might be somebody that we have a history with, but we're working through those things right now," said McVay, who declined to name the potential addition. "So I wouldn't say a workout, but there might be somebody that we would bring in."

After the game Sunday, Kupp said he was "feeling all right" but was "a little stiff."

"I thought I could go out there and play," Kupp said. "I wanted to play. It's just hard not being able to go out there and compete."

Kupp said he felt no ill will toward Stewart for the illegal tackle.

"I know he wasn't doing it with any kind of malice or anything like that," Kupp said. "He checked on me during the game, when I came out there in the second half, he asked if I was good."

Kupp also was sidelined in the second half of a Week 5 victory over the Seattle Seahawks after he was placed into concussion protocol. He cleared protocol a day before facing the Broncos.

A second-year pro from Eastern Washington, Kupp has played a significant role in the Rams' top-ranked offense this season. He has 30 receptions for 438 yards and five touchdowns.