ENGLEWOOD - Charging up the running back depth chart is a pair of fresh legs.

During the Denver Broncos’ training camp practice Saturday, rookie Devontae Booker slid in to rep with the first-string offense, behind C.J. Anderson, ahead of Ronnie Hillman.

In the Broncos preseason game Thursday at Chicago, Hillman was the first back in to replace Anderson with Mark Sanchez at quarterback while Booker came in with Trevor Siemian and the second team in the second quarter.

It’s early yet. The key with running backs is to keep them healthy through the preseason. But if they do, the plan may be for Anderson and the rookie Booker to be the Broncos’ 1-2 running backs this year.

“Probably just the coaches wanting me to get more reps with the 1s,’’ Booker said. “Felt good about it and just continuing to go about the work.’’

We know about the famed one-cut, zone-blocking rushing system Gary Kubiak has used since going back to his days with Mike Shanahan and Alex Gibbs in the mid-1990s. When Booker makes that first cut? There is an explosion there that has the Broncos’ brass thinking they have something special.

“I couldn’t have fell into a better spot, landing here,’’ Booker said. “One cut, zone system. I feel good about it every time we’ve got a run call play, I just one jump cut and go. Get downhill fast.’’

The Broncos thought so highly of Booker coming out of Utah, they considered taking him with their No. 31 pick in the draft. They were able to trade up and get quarterback Paxton Lynch instead.

As the Broncos addressed immediate needs in the second and third rounds by taking defensive lineman Adam Gotsis and safety Justin Simmons, Booker fell to the fourth round because of knee concerns. He had surgery to repair a torn meniscus in his left knee in November. When he was still experiencing discomfort two months later, he had another procedure just before the NFL Scouting Combine in February to shave down his repaired meniscus.

The knee is good now. Don’t give up on Hillman, yet. Running back plans have a tendency to require adjustment by preseason’s end. Booker still has a long ways to go in pass protection if he is to permanently pass the veteran Hillman.

“In college there are probably three pass protections that you have to know,” Booker said. “Here in the NFL the playbook is so big you have to know everything from pass protection and even on run plays when you’re not getting the ball. It’s real broad.’’

Still, if all goes well for the Broncos, Paxton Lynch and Devontae Booker will be big names in Denver for years to come.