ENGLEWOOD, Colo. – Although he appreciates his coach's caution as he embarks on his comeback, Jamaal Charles is hankering for some hand-offs.

The Denver Broncos are holding him back even though doctors gave him the green light this week.

"He's been cleared for everything, but we're not going to push him out there too quickly," coach Vance Joseph said, explaining that he didn't want to risk ruining the dynamic dimension Charles could add to the Broncos' offense.

"If he gets back to being Jamaal," said Joseph, "we've got something special there."

So, his goal is to get Charles to September fresh and fit.

Charles was accustomed to star treatment during training camps with the Chiefs, but this is different. This time, he's coming off two years' worth of injuries, operations and anguish.

During OTAs, Charles said he was happy the Broncos were being patient with him and only allowed him to suit up for the final few practices before the break.

Now that training camp is here, he wants them to turn him loose a little.

"I told them definitely I want to do more," Charles said Friday. "Right now I'm happy with the system. They're taking their time with me and I told them I want a little bit of thud and get hit just to get my confidence up and see where I need to fit my pads and make people miss."

Charles piled up 9,717 yards from scrimmage with 63 touchdowns in nine seasons in Kansas City while piling up a 5.5-yard-per-carry average, best in NFL history. But a career that looked as if it would land Charles in the Hall of Fame was derailed the last few years by injuries that cut short several seasons in his prime.

Charles played in just eight games over the last two seasons after tearing his right ACL in October 2015, leading the Chiefs to cut him this winter to save $6 million in salary cap space.

Charles quickly signed with their AFC West rivals, declaring he'd long admired John Elway and had always wanted to play for the Broncos.

Although Charles can only imagine right now what he might be able to do in Mike McCoy's offense, he likes what he sees in the playbook.

"He's getting running backs out in space. So, it's a nice setup," Charles said. "It just reminds me of (Chiefs) coach (Andy) Reid's system."

The only difference for Charles is he's wearing a brace on his right knee.

"It's really my second day with it, so I really have to get used to it," he said. "If I don't get used to it, I'll throw it away. Right now, it's a safe plan for me to build confidence up in my knee."

QUARTERBACK CAROUSEL: Friday was Paxton Lynch's turn to start and he had two notable plays: a deep completion to Cody Latimer and a 40-yard scramble up the sideline for a touchdown.

"When things break down early on, he can take off and make big plays with his legs," Joseph said.

Trevor Siemian came on strong in 7-on-7 drills at the end of practice, leading three touchdown drives. Although it wasn't as sexy as Lynch's big pass, the coaches surely noticed one play in which Siemian stood up and changed a route call, then hit Jordan Taylor 30 yards downfield on a crossing pattern.

Both QBs are paying the price of facing the league's top secondary but both have had their big moments.

"Paxton was very comfortable today," said wide receiver Emmanuel Sanders, noting in particular a perfectly placed pass he caught from Lynch in the red zone that had some zip on it. "It was just a beautiful throw. I was just like, if he can make those throws consistently, he could be the guy for the job. Then I see Trevor come back and he's throwing off his back foot, a perfect throw. Both of them want the job."

It won't be won or lost until the preseason slate begins with a trip to Chicago on Aug. 10.

"That's what's going to determine who the starter is, who can ball during the game," Sanders said. "Practice is practice. You have to be able to take that to the game."