Sunday was bittersweet for Denver Broncos quarterback Peyton Manning. Playing against the Kansas City Chiefs, Manning broke Brett Favre’s NFL record for most career passing yards when he completed a 4-yard pass to Ronnie Hillman in the first quarter. But aside from setting that new all-time high, Manning could scarcely have had a worse day. It was, statistically, the worst performance of his career — he went 5 for 20 with 35 yards, zero touchdowns, four interceptions and two sacks — and it ended with Manning benched in the third quarter amid a chorus of boos. (Later, we learned that Manning had a partially torn plantar fascia in his left foot.)
It was also a tough game for us here at FiveThirtyEight. We’re on record as considering Manning to (probably) be the greatest quarterback in football history, an opinion informed by everything from his personal statistics to his comebacks and the catastrophic harm that came to his team when he was unable to play. So our jaws were agape as we witnessed the once-great Manning throw incompletion after incompletion, pick after wobbly pick.
But one game does not change a guy’s legacy. Manning has been so good over his career that he’d have to replicate his Sunday performance — a game so bad it ranks among the worst two dozen or so in modern NFL history — every week for nearly an entire season before he ceased to be the top statistical passer ever.
To figure out how good Manning has been, I used a formula created by Chase Stuart of the excellent FootballPerspective.com.1 The formula is based on Pro-Football-Reference.com’s adjusted net yards per attempt, and it judges the value that a quarterback accumulates over a league average quarterback.2 Applying it to every QB’s numbers since the 1970 AFL-NFL merger — and adding a wrinkle in which we also compare his adjusted yards to those of a backup-caliber passer — we can generate a list of the greatest statistical quarterbacks of all time:
|CAREER ADJUSTED YARDS OVER …|
|PASSER||GAMES||STARTS||A BACKUP QB||LEAGUE AVERAGE|
According to our version of Stuart’s metric, Manning didn’t need to break Favre’s yardage record Sunday to cement his status as the G.O.A.T. That’s because he owned that distinction as far back as 2012, when his lifetime values over both an average and a backup passer outstripped those of former Dolphins QB Dan Marino. Since then, Manning has continued to add to his greatness, particularly after he posted yet another of the best passing seasons ever in 2013.
Now the gap between Manning and the field is so wide that it would take Manning 12 consecutive games exactly like his outing Sunday (299 adjusted yards of value below average, by far the worst game of Manning’s 17-year NFL career) for Manning to fall behind Marino in those value over average rankings. And if we’re comparing Manning and Marino to backup QBs rather than average ones, it would take 15 straight games like Sunday’s (-282 adjusted yards of value, again the worst game of Manning’s career) for Manning to dip below Marino and into second place.
In other words, Manning is pretty firmly entrenched as the best statistical passer ever. Even though he was way (way!) off his game on Sunday and his plantar fascia injury could have serious repercussions for his career going forward, Sunday’s dreadful game in some ways serves to help us further appreciate how great Manning was when he was at his best.