PITTSBURGH — Is a broken Peyton Manning the only way to fix a Broncos team that’s falling apart?

Standing in the middle of a dejected locker room Sunday after Denver’s stunning collapse in a 34-27 loss to Pittsburgh, Manning looked me in the eye. His voice exuded a presidential calm and the tie he wore was knotted perfectly, but the five-time MVP was ticked, and he did not hide his frustration.

“It’s miserable not being out there, when you’re losing the games,” Manning told me. “You know how hard the guys work. And that was a heart-breaking loss. Win or lose, it’s hard not being out there. But when you lose, it stings more.”

Frustrated in the knowledge it will be impossible for his injured left foot to heal 100 percent for the remainder of the season, Manning nevertheless will meet Monday with coach Gary Kubiak to determine if he has a shot of getting back in uniform for the Broncos’ next game against Cincinnati. What’s more, the 39-year-old quarterback is insulted by any suggestion that serving as a backup to Brock Osweiler is beneath him.

After a second consecutive defeat dropped Denver’s record to 10-4 and put the Broncos’ lead in the AFC West in jeopardy, there’s an increased sense of urgency for Manning to return from a partially torn plantar fascia that has sidelined him since being pulled Nov. 15 from a game against Kansas City. The challenge for Manning is to determine if he can play effectively enough to help the team while dealing with the slow-healing injury.

“The doc said that you’ve got to get it to a point of being able to manage it. He said: ‘If you really want to feel great, go to the beach for two months,’ ” Manning told me.

“So you’ve got to get to a point where (the injury) doesn’t affect you, and it doesn’t affect other parts of your body. That’s my goal. Looking back on it, I probably played on it where it compromised me. And I know I don’t play as well as I used to when I’m not feeling as well as I’d like.”

After winning three straight games with Osweiler as the starting quarterback, the Broncos have yet to score a point in the second half of games during the month of December. Osweiler engineered four touchdown drives as Denver built a 27-13 halftime lead against Pittsburgh, then completed only 7-of-26 passes for 82 yards in the second half.

Let the quarterback controversy begin.

“I want to get to feeling as good as I can, and be as honest with Kubes and as honest with myself as I can. You want to avoid compromising to the point where you can’t do your job. It’s not fair to anybody,” said Manning, whose quarterback rating in nine games was 67.6, the lowest of his career. “What I’m shooting for is to get to feeling good and feel like you can do your job.”

Before the game against Pittsburgh, the NFL Network aired a report by Ian Rapaport that said Manning was chafing at the idea of serving as a backup to Osweiler, and citing an unnamed source, suggested Manning was inclined not to accept a supporting role as the No. 2 quarterback in Denver.

“It’s a flat-out lie. It’s insulting. And it’s distracting.” Manning said. He spoke calmly but refuted the report in the strongest terms. “That’s 100 percent bull—-. No. 1, it is bull—-. And No. 2, it’s insulting. The worst part about being hurt is that a lot of people seem to know everything about you and speak for you, even when it’s somebody you don’t even know.”

Manning insisted he is willing to help the Broncos in any capacity that Kubiak deems best. As proof, he cited enthusiasm for being allowed to travel to Pittsburgh, where Manning was not named to the active roster but stood on the Denver bench, where he offered advice to Osweiler and the coaching staff.

“To get back on the practice field was a major step,” said Manning, who practiced with the team Wednesday and Thursday, before taking Friday off as soreness developed in his left foot.

“The idea now is not to go backwards. The next thing is to not be thinking about it as you’re stepping and throwing. It’s to not be in pain as you’re stepping and throwing. It’s seeing if you can go through a whole week of practice. It probably feels best when you’re not on it. In order to be able to play, you’ve got to be able to stay on the field for a full week of practice.”

Will he be ready to play against the Bengals?

“It’s hard to do the what-ifs,” said Manning, who needs to see how the injury responds to the stress of a full week of practice.

The helplessness of being hurt is a real pain.

“When you’re injured, everybody asks you how you’re doing, because people think that’s what they’re supposed to do. And I tell them: ‘Oh, it will start feeling better, just as soon as I amputate it,’ ” said Manning, proving his foot might be sore but sense of humor is robust.

Mark Kiszla: mkiszla@denverpost.com or @markkiszla