ENGLEWOOD, Colo. -- Whatever else happens in what remains of Jamaal Charles' football career, Kansas City will always be the place where he became a five-time Pro Bowl running back with five 1,000-yard seasons and a pile of touchdowns.

And Denver will always be the place where he believes he showed he wasn't done just yet.

"He's an amazing guy and I'm proud of him for being able to come back and do what he's doing," Kansas City Chiefs coach Andy Reid said this week. "He's going to go down as one of the all-time greats in the National Football League and definitely for the Kansas City Chiefs. ... He's a great kid."

Charles, who turns 31 in December, is in his 10th NFL season. He will run on to the Arrowhead Stadium field once again Monday night (8:30 ET, ESPN), this time in a Denver Broncos uniform. The moment will be the intersection of history, emotion and the unshakable belief he could return from last season's knee surgeries.

The Chiefs selected Charles in the 2008 draft, and he became one of their marquee players with 63 total touchdowns in 109 games. His 5.43 career yards per carry average, much of it accomplished with the Chiefs, is the highest among any back with at least 500 attempts.

Then he tore his right ACL in October 2015 -- the second such tear of his career given he had torn the left one in 2011 -- and in the aftermath he had multiple knee surgeries in 2016. He played eight games combined in those two seasons and the Chiefs -- who were of the opinion that Charles' knees would no longer allow him to play in their offense -- released Charles in March.

He said they "fired" him shortly after he signed a one-year contract with the Broncos this past spring, a deal that came to fruition after Charles said two other teams (Seattle and San Francisco) had told him his knees would no longer allow him to play. It's why Charles, a rotational player in the Broncos' backfield with 196 yards on 42 carries, says he thinks just being in a uniform has surprised many.

"Just taking hits and keep getting back up," Charles said Thursday. "The other two teams that looked at my knees basically said 'You should retire.' But I think I proved to people I can still play right now, that I can still play with anybody, and keep showing it. That's been lighting the fuel in me, keep that spark inside me."

After the Broncos' medical staff examined Charles in free agency, the team came away with the idea that Charles could have an impact on their offense if they were careful about how they dispersed his workload. They held Charles out of their on-field work for most of the offseason program and limited him in training camp.

Charles then played in just one preseason game; Broncos coach Vance Joseph consistently said the start of the regular season was the goal for Charles. All along the Broncos believed they had seen, in practices, Charles' potential in their offense as a change-of-pace player they thought still had the speed and vision to make an impact.

"Yeah, I think I proved that Week 1, suiting up. ... I just hope I continue to make plays," Charles said. "I want to do that every week."

Charles has had as many as 10 carries, in the season opener, and as few as four in the loss to the Los Angeles Chargers. He has said he believes he could still do more moving forward and joked the Broncos should "take the training wheels off."

He has played much of the time in the team's three-receiver set and has eight receptions this season.

"He's been so cool to watch," Broncos quarterback Trevor Siemian said. "You go back to when we got him. You're not quite sure until you see him live how he's going to play and look. To be playing with him, he's been so impressive. His leadership in the locker room is so great with everybody. He's really cool to be around."

Chiefs rookie running back Kareem Hunt, the league's rushing leader, said this week he continues to "hear a lot of stories ... good stories" about Charles. Reid said he was glad the Broncos could see what kind of player and person Charles is. For his part Charles, who called current boss John Elway his favorite player growing up, said he has kept things in check for much of the week and that a win would be the most important thing.

"I'll always be a Chief ... I have so much history [there]," Charles said. "Lot of sad memories, lot of happy memories. At the end of the day, I'm just going out there to play football."