PHOENIX — Peyton Manning has reached that now-and-forever age of 39 and adjustments must be made.

What to do with someone so young? Manning, who has been breathing for 39 years and 1 day, might be the NFL’s oldest position player.

But three kickers — Adam Vinatieri, Phil Dawson and Matt Bryant — are older. And Manning is a long way from setting any old-man records. The NFL counts 18 quarterbacks who played after their 40th birthday, including Brett Favre at 41, Doug Flutie at 43 and Warren Moon at 44.

Still, Broncos coach Gary Kubiak has held preliminary talks with Manning about having the quarterback save his mind and body for spells during the 2015 season.

Backup quarterback Brock Osweiler is young and eager to play after serving a three-season apprenticeship as Manning’s understudy.

“I think as a coach you have to make those suggestions to players,” Kubiak said Tuesday during the AFC coaches’ breakfast at the Arizona Biltmore resort, where the league is holding its annual league meetings. “But sometimes with the great ones, the reason they’re great is you have to battle them on things like that because they’re used to being a part of it every day.

“I want to do what’s best for him. I went through the same process with John (Elway) late in his career, and it was a battle for me and Mike (Shanahan) to do some things with him.”

Kubiak said adjustments were made in 1997-98 with Elway in regards to meetings, practice and training camp, meaning Elway did less.

One other concession Kubiak will make for young man Manning: The coach will bend his offensive system to fit the quarterback’s skill set rather than have the quarterback fit the coach’s scheme.

“I’m the one who has to adjust and find out how I’m going to mesh everything together,” Kubiak said. “That’s what we’ve been doing, and I told Peyton that from the start. We are going to run his offense and do what he does best, but it’s going to be the Broncos’ offense.

“Obviously, I love to run the ball, and I love the play pass. I love to do those things, so there is going to be a commitment there, but there is 17 years of investment in what he’s done better than anybody, and we’re not going to run away from that.”

It’s a stretch to say the Broncos have put Manning on notice. It’s not that he’s competing with Osweiler for the starting quarterback job.

Yet, the Broncos forced Manning to take a 21 percent pay cut this year. And somehow, someway, the Broncos need to find out what they have in Osweiler, a second-round draft pick in 2012 who has yet to start an NFL game. Osweiler’s contract expires after this season.

“What I tried to do was go back and watch his practice,” Kubiak said of Osweiler. “He’s got a bunch of ability. He’s a big, strong kid. He’s smart, he can move around.

“Now I’ve got a chance to get my hands on him and work with him. But what I’m so impressed with is how excited he is. Wanting to get going, wanting to play. I know he wants to be a part of the Broncos’ organization. He sees himself as a starter, that’s the most important thing, and that’s what you want.

“His opportunity is going to come at some point, and it’s our job to make sure he’s ready to go. And it’s his job. I always tell young players nobody knows if you’re taking care of your business until you’re thrown in the fire.”

Mike Klis: mklis@denverpost.com or twitter.com/mikeklis