ENGLEWOOD, Colo. — Scale back the playbook for a quarterback making his first NFL start? Not when that man is Brock Osweiler, Peyton Manning’s fourth-year understudy who has a stronger arm and better mobility than the ailing 39-year-old icon.

Denver Coach Gary Kubiak said he won’t have a mini-menu of play calls Sunday when the Broncos (7-2) visit the Chicago Bears (4-5).

“No, I feel very comfortable with Brock,” Kubiak said. “I could go give him all of the work, mentally, that he needs. He handles everything well, but I think there is a point where you go back, you study him and you see what he’s done, and what he feels most comfortable with.

“As far as volume of game plan and stuff, I’m very comfortable doing anything with him.”

While nobody can decipher defensive intentions at the line of scrimmage like Manning can, Osweiler, who turns 25 on Sunday, displayed the athleticism and mobility to run Kubiak’s bootlegs last week.

He escaped tacklers in the pocket like Manning hasn’t done in a decade. He hit receivers on the run with more zip on his throws than Manning’s been able to muster this season. And he commanded the huddle like a seasoned vet after Manning was benched following his fourth interception in Denver’s 29-13 loss to the Chiefs.

“He came in with a bunch of swagger leading the huddle,” said receiver Cody Latimer.

To go with a huge smile, noted tight end Virgil Green.

“There weren’t too many other guys with that kind of smile,” Green said. “I think he tries to model exactly how Peyton takes the huddle, and when he got in the huddle last week he came in there and said, ‘Let’s keep fighting. Let’s keep working. Let’s keep grinding.’ That’s all you can ask for.”

The prevailing notion is that Osweiler’s athleticism and mobility will allow the Broncos to run a more traditional Kubiak-style offense while Manning sits out and tries to get healthy.

Manning is dealing with foot, rib and shoulder ailments, and his franchise-record 57-game starting streak will end Sunday. Manning has never missed an NFL game outside of the 2011 season he missed after a series of neck surgeries threatened his career.

Kubiak is considering leaving Manning behind in Denver to continue getting treatment.