Peyton Manning's birthday a reminder the football clock is ticking

ENGLEWOOD, Colo. -- Denver Broncos quarterback Peyton Manning turned 39 years old Tuesday.

He will officially begin his return for his 18th NFL season when the Broncos open their offseason program next month. He already holds, or is tied for, 25 significant NFL records.

And any of the major records he doesn’t have at least a share of -- career passing yards is likely the most notable missing -- he will reel in during the coming season if he simply plays at his career pace. After all, since he signed with the Broncos in 2012 he is averaging 309.7 passing yards per game. The Broncos have won 13, 13 and 12 games, respectively, in those seasons, with three division titles.

Shortly after he was hired by the Broncos as head coach, Gary Kubiak looked at the team's game video from this past season and said: "He’s got a lot of good football left in him. I’m excited to work with him, excited to see him up close, have those back-and-forth exchanges that make everybody better. He’s one of the best to ever to do it, and I’m really excited about building an offense for him, for our team, so we can get done what we all want to get done."

So, where Manning is right now isn’t uncharted ground -- five quarterbacks in the Hall of Fame, including kicker/quarterback George Blanda, played in the NFL past their 40th birthday. That means the other quarterbacks enshrined in Canton, as Manning will be five years after his last NFL game, were out of the game before their 40th birthdays.

In the not-so-distant future Brett Favre will be the sixth Hall of Fame quarterback who played beyond his 40th birthday, but he threw 19 interceptions and 11 touchdown passes in his last NFL season. Dan Marino retired when he was 38, Joe Montana at 38, Dan Fouts at 36, and Manning’s boss, Broncos executive vice president of football operations/general manager John Elway, retired when he was 38.

But times have changed some. Manning is coming off a 4,000-yard passing season -- his 14th. Though he didn’t look like himself in the pocket down the stretch last season, his 4,727 passing yards were the second-highest single-season total of his career, and his 39 touchdowns were his third-highest single-season total.

Looking at his age, their cash reserves, their salary-cap situation, and with an eye on the future, the Broncos asked Manning to take a pay cut this offseason. He agreed to a $4 million salary trim that he will earn back if the team wins the Super Bowl.

Manning’s mood has been a topic of conversation since the deal was done. Some wonder how Manning will fit the new offense, how a player averse to surprises will transition to his third offensive coordinator/play-caller combination in his four seasons with the Broncos. For his part Kubiak said: "We’ll have things in place that fit and he does well, because we’d be stupid not to."

The Broncos also find themselves in an occasionally uncomfortable spot as they try to balance maximizing Manning’s presence with the franchise with the directive owner Pat Bowlen has long passed down to all team officials -- that the Broncos get in win-now mode and stay in win-now mode after even the likes of Elway and Manning are done behind center.

As Manning blows out the candles on another spring birthday, the Broncos are again in the Super Bowl conversation. Whether they are good enough to rise to the season’s biggest moments and close the deal remains to be seen.

Manning has always said he is "year-to-year" at this point in his career.

He’s not the oldest future Hall of Fame quarterback with at least one Super Bowl win on his resume to play in the league. However, that list gets shorter every year as the list of players he has passed grows. But there is no question Manning would wait for his favorite football present until, oh, about Feb. 7, 2016, to play in the game that lured him back for another season -- with a pay cut -- in the first place.