To find the true measure of what Peyton Manning meant to football, don't bother poring over the highlights from his record 186 wins, or re-watching either of his Super Bowl victories, or looking at a single throw he made on his way to a record-setting 71,940 passing yards over 18 seasons.
Instead, simply wait until September. When it comes, pick any weekend, turn on any game — pro, college, high school — and watch quarterbacks lining up in the shotgun, changing plays at the line of scrimmage, dissecting defenses at will and rolling up numbers that were once deemed unthinkable.
All those quarterbacks are doing what Manning showed was possible. He created the passing game as we know it in 2016 and, in turn, forced defenses to adapt and disguise and get better. He won as much with his mind as his arm, and put as much work into Monday through Friday as he did when he suited up on Sunday.
"It's not to say audibles didn't exist before Peyton Manning came around, because they did," said Tim Hasselbeck, the former NFL quarterback who is now an analyst for ESPN. "But he'd go to the line of scrimmage with the ability to get to the play that would be best for the defense out there. You look around the league at what other teams were trying to do, and they were trying to emulate what Peyton Manning was doing as a quarterback."
Set on the notion that every defense had a weak spot, the Colts-turned-Broncos quarterback spent hours analyzing them, the way a wealth manager looks at stocks. Then, on Sundays, he tore them apart. His calls of "Omaha, Omaha" — whatever that meant — were as frustrating to the defenses as they were entertaining to those counting along at home.
In short, Manning obliterated the long-held notion in football that the word "pass" automatically had to be associated with "risk."
"You changed the game forever and made everyone around you better," Manning's biggest rival, Patriots quarterback Tom Brady, said in a shout-out to No. 18.
So, the question becomes, where does Manning rate among the all-time greats?
Like almost everything else he touched over nearly two decades in the NFL, Manning has recalibrated this question.
Measured by mere Super Bowl titles, he is beaten — with two fewer than Brady, Joe Montana and Terry Bradshaw.
Measured by mere athleticism, he cannot stand up to John Elway's grit or Dan Marino's arm or Steve Young's combination of speed and precision.
He didn't have the common man's, swashbuckling style of Kenny Stabler and Brett Favre, or the ability (or need) to constantly absorb the game's brutality, a la Troy Aikman and Fran Tarkenton.
But pointing out the obvious is selling Manning short, especially considering the brutally difficult comeback he made after four neck surgeries that, in many minds, should have put him out of the game forever.
Starting at Square One, barely able to release the ball from his hand, Manning rebuilt his game and played four years in Denver, leading the Broncos to two Super Bowls, one title, and, in 2013, directing the most prolific offense in NFL history.
The last season, and the last few months, were, in a strange way, the most impressive.
Burdened with a bum foot that sent him to the bench for six weeks, Manning did the grunt work of a rehabilitating backup. Only when the Broncos bogged down in the regular-season finale did he get back in the game. He checked to the right plays, didn't try to do too much and let the defense guide the way. Manning completed only 13 passes and Denver gained only 194 yards in last month's Super Bowl victory over Carolina — the lowest yardage total ever for a winner.
That Manning was willing to go with the flow, not fight it, spoke volumes of the kind of quarterback he really was.
His legacy, he said, wasn't about the five MVP awards, the 539 touchdown passes and all the rest of the records.
"For me," he said before the Super Bowl, "it's being a good teammate, having the respect of my teammates, having the respect of the coaches and players."
While changing the game, he also burnished a remarkable off-the-field career — showing fans and fellow players that, yes, when the time is right, you can do the commercials, do the funny on "Saturday Night Live," build multimillion-dollar charities and somehow come off like the guy next door.
Too good to be true?
Maybe. The last few months have been checkered with reports that linked him to human growth hormone and a rehashing of a sexual harassment claim from his days at Tennessee.
Those stories will play out, and could ultimately harm Manning's legacy.
But for almost anyone who played with him, or coached him, there's not much left to debate.
In an interview three years ago, Manning's college quarterbacks coach, David Cutcliffe, spoke about one of the first plays any Tennessee player had to learn when they arrived in Knoxville in the 1990s. It was a staple of the offense, called "62 Meyer."
During the summer leading into his freshman year, Manning studied the play, then took three pages' worth of his own handwritten questions and gave them to Cutcliffe before fall practice started.
Ultimately, Manning almost always figured out the answers — at Tennessee, then in Indianapolis and, finally, during his four years in Denver.
"He redefined preparation," Cutcliffe said. "He redefined the quality of the work that's expected of the people around him."