DENVER — It was a scary moment, to be sure.

Starting a drive midway through the second quarter, head coach Sean McVay called a jet sweep to the right for wide receiver Cooper Kupp. With the play well set up on the right side, the Eastern Washington product took the handoff from quarterback Jared Goff and gained first-down yardage.

But then he was taken down by an illegal horse-collar tackle, with his left knee appearing as if it may have sustained a serious injury.

Kupp stayed down on the Broncos sideline in obvious pain, and he was eventually carted off the field. The Rams' offensive players all came over to wish him well as Kupp rode off into the tunnel for further examination.

"I go out there for every player, just because you care about these guys, No. 1. The injuries is probably the worst part about this — when you see these guys go down," head coach Sean McVay said. "Just knowing the type of player that Cooper [Kupp] is and how tough he is, for him to be grabbing his knee like that, you're always unfortunately thinking that the first thought is always the worst."

"I kind of missed the hit initially, the horse collar — missed the ending of it. But horse collars usually end up bad for the legs," wide receiver Robert Woods said. "But just seeing our guy go down, said a prayer for him — especially when our guys get carted off."

Kupp didn't know the full extent of what was wrong, but said he "knew something happened — it definitely hurt enough."

"It was my first time doing something like this, so I didn't really know what to expect," Kupp continued. "I had to just come in here and get some things looked at and after we were kind of able to clear some things off, the pain kind of calmed down a little but and I was able to try it out."

Kupp went through some tests in the locker room, and when the results came out in a positive manner for him, he began to prepare to play the beginning of the second half with team doctors and head trainer Reggie Scott.

"I came in here, got things checked out, kept it warm during halftime — got on the bike, tried a little bit of running out there right before we head back onto the field," Kupp said.

"When he was going through those tests with the docs, it seemed like what he went through initially turned out good, then once you kind of settle down a little bit he wanted to give it a shot there coming out for the second half," McVay said.

That happened, with Kupp playing Los Angeles' first offensive series to open the third quarter. But with Kupp still clearly feeling the effects of the knee injury, the team elected to hold him out for the rest of the contest. The second-year wideout nevertheless stood on the sideline with his helmet on through the final whistle.

"Coming out of halftime I thought I could go out there and play. I wanted to play," Kupp said. "It's hard not being able to go out there and compete — you feel like you're letting the guys down not being able to go out there and give it your all. For me, I'm always going to go out there and push and try to get back on the field and play, but it comes down to what's best for this team long-haul — what Reggie and his training staff believes is best for us."

"He played that first drive and did some things," McVay said. "But you can just see there's a difference when you're out there gutting through it and then when you're out there able to be a great guy with short-space quickness, the lateral agilities to be able to work edges on people in the pass game, all the different things that we ask him to do in the run game — he just wasn't himself."

Still, just seeing Kupp attempt to play in the second half meant something to his teammates.

"We know this team is full of tough guys, battlers, and fighters. We know he's going to want to be out there regardless — and was still fighting to get out there and play with us," Woods said. "But just seeing him out there, knowing it's not as serious, seeing him on the bike, seeing him move, we know it's a short timetable with his return."

Addressing the media postgame, Kupp said he was feeling "alright" with his knee feeling "kind of stiff," but added that he felt like he'd be good going forward. He also noted that despite the fact that the play where he got hurt was a penalty, he wasn't angry with Broncos safety Darian Stewart.

"You never want to get hurt, but I hold no ill-will towards Stewart. 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 — came out during the second half, asked if it was good. But it's a game. It's tough, I know if I was playing defense and that was the only way that I was going to be able to get someone down, in the heat of the moment it's tough to know if you make that tackle or let that guy go. It's tough, I understand it, I understand why it's a penalty too obviously — you want to avoid guys getting hurt — upset obviously that I got hurt, but I'm not holding any ill-will towards Stewart."

Kupp will likely undergo further tests to determine with certainty the severity of his knee injury on Monday.