SANTA CLARA, Calif. — Peyton Manning’s body is no longer fit to play football.

Not at this level. Not in Super Bowl 50, at the pinnacle of the sport, when his counterpart (Carolina star Cam Newton) is one of the most physically gifted football players of all time.

Physically, Manning is no longer the quarterback he once was, the passer who spent 13 seasons in Indianapolis tearing apart NFL secondaries.

Manning found a way to get back to the mountaintop anyway.

“Certainly, I have some physical differences with the years I have played, certainly since my major injury four years ago,” Manning said. “I think it is about learning to adjust, learning to adapt. Using the baseball analogy, the guy that used to throw 95-plus as he gets older, maybe he can’t still throw that same fastball, but he can work the corners of the plate and still strike a guy out. I feel like I can still move the chains.”

Manning is 39 now, the oldest quarterback to start a Super Bowl. With that distinction comes the expectation of a little physical decline, but football has offered an array of possibilities for aging quarterbacks. Manning’s eternal rival, Tom Brady, is 38. The Saints’ Drew Brees is 37. By virtue of durability, preparation and some luck, Brady and Brees look as fit as they ever have been, two legends finding a way to extend their athletic life spans in ways we’ve rarely seen.

Manning’s situation is nothing like his contemporaries’. The aging legend has had his fair share of tissue injuries; he tore his right quadricep last season and tore his plantar fascia in his left foot this year. As painful as those injuries are, a player can bounce back.

Manning’s body broke down at a structural level. A herniated disk in his neck forced three surgeries in 2011, ended his stretch in Indianapolis and changed the way he had to approach the game.

“My arm has not been the same since I got injured four years ago,” he said. “It just simply hasn’t been. I had a strange injury. I had a neck injury that caused some nerve problems in my right arm. ... I’ve worked hard to sort of manage with the physical limitations and have gotten to a place where I think I could be effective.”

Manning found out later that his body has other structural problems.

“When you have surgeries, the doctor sometimes will mention to you, whether you ask him or not, ‘Hey, you are probably heading for a hip replacement at a certain time in your life,’ ” Manning said. “I said, ‘Doc, I didn’t ask you if I was going to have a hip replacement. I didn’t need to know that right here at age 37, but thanks for sharing. I look forward to that day when I am 52 and have a hip replacement.’ ”

Few quarterbacks could continue to start at a playoff level after going through everything Manning has endured.

But his legacy was never about physical gifts. He never had the arm of John Elway or Brett Favre. He never played with the mobility of Steve Young or Fran Tarkenton. Few put his release in the same category as Dan Marino’s.

Manning’s best asset has always been his brain.

A new game plan

Quarterback has always been the most cerebral position on the field. Manning took it to another level.

Fanatical about preparation, Manning became a de facto offensive coordinator on the field, operating out of the no-huddle at will, making frantic adjustments at the line of scrimmage, directing the offense from the comfort of the pocket.

“I think he is probably one of the best guys at the line of scrimmage who has been around it a long time,” Carolina linebacker Luke Kuechly said. “He can switch stuff and get them into plays that allow them to be successful. He sees defenses and knows where he is going to run the ball and where he is going to throw it.”

For a couple of seasons after his surgery, that was enough. Despite the diminished arm, Manning took the Broncos to the Super Bowl in the 2013 season by torching the NFL for a league-record 5,477 yards, a league-record 55 touchdowns and just 10 interceptions. No matter what had happened to his arm, the brain was still good enough.

And then the body started to catch up with him. Manning tossed 12 interceptions in the final nine games of 2014, hampered by the torn quad, and opened this season by throwing nine touchdown passes against 17 interceptions before the torn plantar fascia shut him down and he handed the reins to backup Brock Osweiler.

“I think the biggest thing was getting Peyton back to himself, him being healthy again,” coach Gary Kubiak said.

But Manning hasn’t truly been healthy for years.

The real magic of this playoff run has been his mental evolution. For his entire career, Manning has been the focal point, the straw that stirs the drink. And when Kubiak inserted him back into the lineup in the season finale against San Diego — he originally had stuck with Osweiler as the starter — a very different Manning emerged. In the playoffs, Manning has avoided turnovers, played the field-position game and resisted the urge to try to win it himself.

“When you get a little bit older and you get up there in age, he had some health issues and he worked through those and was able to come back and get us to this point,” said Elway, now the Broncos’ executive vice president and general manager. “Peyton has done a nice job the last couple weeks of being careful with the ball and not turning it over and making the big plays when he needs to.”

Elway knows better than most what Manning has been forced to do.

After years of carrying flawed Broncos teams to the Super Bowl, Elway finally won two titles at the end of his career in a very different role — a game manager who won behind a Terrell Davis-led running game and a solid defense.

That’s what Manning is doing now. After the Broncos’ previous Super Bowl defeat — that brilliant 2013 season ended with a demoralizing 43-8 loss to the Seattle Seahawks — Elway went to work assembling the best defense in the league, ensuring the Broncos no longer needed Manning to be an all-world player to win.

“It says a lot that he’s been able to perform at an extremely high level — whoever he’s playing for, whatever offense, whatever head coach, whatever team,” New York Giants quarterback Eli Manning said. “He worked extremely hard, changing to a different franchise, towards the end of the career. Obviously, this year, brand-new offense, adjusting to that offense, dealing with some injuries, he’s done a good job understanding the circumstances and situations and doing what it takes to get them here.”

‘The task at hand’

Manning cannot play forever. His body has made that abundantly clear.

And the spectre of retirement has been everywhere during Super Bowl week. With a chance to play in the Super Bowl, to go out on top like Elway did, Manning has been asked over and over if he plans to retire after Sunday’s game.

“I haven’t made up my mind, but I don’t see myself knowing that until after the season,” Manning said. “Whatever cliché you want to use, but I kind of stay in the moment and focus on the task at hand.”

His inner circle has offered no hints. Eli would only say that he can’t see his older brother playing for anybody other than the Broncos, who have a decision to make in the final year of Manning’s deal with a capable Osweiler waiting in the wings.

Elway, an adviser whom Manning consulted when he arrived in Denver about playing quarterback over the age of 35, said the two haven’t talked this week about the quarterback’s future.

“The bottom line is that he’s trying to concentrate on winning a world championship, because that’s what it’s all about,” Elway said. “That’s what he’s worked for this whole season and throughout his career, and he’s getting another opportunity with his fourth appearance here. ... He’ll have plenty of time this offseason to figure out what he wants to do. He doesn’t need to be thinking about that now.”

Manning has followed that blueprint all season. When the Broncos decided it was time to shut him down, Manning focused on getting healthy. When he didn’t return right away, he worked at throwing in Denver’s indoor facility. Finally healthy before the season finale, he had to be a backup, but he said he was excited to be able to contribute on game day.

He’s taking the same approach into the Super Bowl. Manning is the sentimental favorite, the aging star trying to ignore the future and live in the moment at least one more time, taking one more shot at the pinnacle of the sport he dominated for so long.

“I think it is important to use all of your experience to your advantage. I think you can always refer back to prior situations and two-minute drives or a fourth-and-goal from the 2-yard line,” Manning said. “I feel like I can still move the chains — maybe in different ways. That is being flexible and being able to adjust. I think that has served me well.”

His body is no longer the same.

But Manning’s defining asset is stronger than ever, ready for at least one more ride.