The Chiefs put Rashee Rice on injured reserve Thursday, sidelining him for at least four weeks and likely longer, after their leading wide receiver hurt his knee when quarterback Patrick Mahomes collided with him trying to make a tackle last weekend.

Mahomes had just thrown an interception to the Chargers’ Kristian Fulton and both players were trying to chase him down. Rice got there first and stripped Fulton of the ball, just as Mahomes dived toward the pile and hit his teammate just above his right knee.

Mahomes said Thursday that he didn’t know he was the one who caused the injury until he saw the replay on the scoreboard. He said he felt bad about what happened.

“I wasn’t really worried about myself. I was worried about his injury and hopefully that it wasn’t as bad as it looked,” he said ahead of Monday night’s game against the Saints.

The Chiefs initially were concerned that Rice tore his ACL, which would mean season-ending surgery. But there has been no official diagnosis, and Chiefs coach Andy Reid said Thursday that the medical staff was waiting for the swelling to subside before they do another round of imaging next week to get a fuller picture of the damage.

Despite leaving the 17-10 win over the Chargers early, Rice still leads the team with 28 catches for 288 yards and two TDs.

“We’re really hoping that things work out for the best, but let’s just see where it goes and leave it up to the doctors to see,” Reid said.

The NFL trade deadline is Nov. 5, so the Chiefs have time to survey the landscape if Rice will miss extended time and they want help from outside the organization. Otherwise, they will lean on JuJu Smith-Schuster and Justin Watson to help first-round draft pick Xavier Worthy and four-time All-Pro tight end Travis Kelce pick up the offensive slack.

“There’s not another Rashee,” Reid acknowledged. “There’s other guys though that are very, very good, so we’ll be fine.”

BIG STEP FOR CHUBB >> Those first moments for Nick Chubb back on the field, back among his Browns teammates, were astounding.

“It didn’t feel real,” Chubb said. “It felt like a dream.”

More than a year after Chubb’s left knee was wrecked on a routine running play for the second time, the Pro Bowl back returned to practice this week, a major step in a comeback few doubted would happen.

“I feel like I’ve been up and battling this for a while now,” Chubb said Thursday, adding his surgically repaired knee withstood his first workout. “It was great to get all that off my shoulders and finally get back out there.”

Back in his No. 24 jersey and orange helmet, Chubb practiced Wednesday for the first time since undergoing surgery after he got hurt on a hit in Week 2 last season at Pittsburgh. The 28-year-old needed two operations to repair two ligaments, meniscus and his medial capsule.

He’s been working his way back since. Running. Lifting weights. Doing all he can to get as close as possible to being Nick Chubb, game-breaking back.

He still doesn’t know if that’s possible.

“I guess we’ll all find out at the same time,” he told reporters.

Chubb won’t play this week against Washington, but there’s a chance he could be active for next week’s game at Philadelphia. In designating him to return to practice, the Browns (1-3) have a 21-day window to add him to the roster.

Chubb has his own timeline to when he’ll play.

“Whenever I feel good,” he said.

“Once you get out there and you’re running around, it’s like you’re 8 years old again,” said Chubb, who has rushed for 6,511 yards and scored 48 touchdowns.