Josh Allen's 2020 fantasy football season was nothing short of extraordinary.
His 396.06 fantasy points paced all players, and were the fifth most in history by any quarterback. He made huge strides in his vertical passing -- throws that traveled at least 15 yards beyond the line of scrimmage -- completing 53.2% of them and totaling 11 touchdowns, after completing only 35.0% with 13 touchdowns on those attempts in the previous two seasons combined.
Allen even led his Buffalo Bills to the AFC Championship Game, ultimately losing to Patrick Mahomes and the Kansas City Chiefs, though he did manage a respectable 287 yards and two touchdowns with one interception in that game.
Clearly, with the improvements he has made, Allen has established himself as one of the best up-and-coming quarterbacks in the game. By all rights, he's much closer in terms of true talent to the 2020 than the 2019 model.
But Allen's chances of repeating or exceeding such a campaign aren't great.
Allen's gains on vertical throws
Kudos to Allen for the aforementioned improvements he made on these throws in 2020, which, while data isn't available from the 20th century, easily ranks among the greatest gains by any individual quarterback on record. He scored 31.9 more fantasy points on these throws in 2020 than he did in 2019, going from a total liability in that department at the time of his 2018 draft selection to having the third-best adjusted completion percentage and 11th-best QBR among qualifiers last season.
The problem, however, is that performance at the level Allen exhibited in 2020 hasn't been sustainable for almost anyone since the metric began being tracked in 2001. There were only 31 instances of a quarterback completing at least 50% of his vertical pass attempts in a qualified season in the century's first 19 seasons. Of those 31, only eight increased their fantasy points on vertical throws the following season.
The group, meanwhile, regressed by 8.2% in terms of completion percentage, by 1.5 yards per vertical pass attempt and by 0.11 fantasy points per such attempt. For Allen, the latter means a drop-off of nearly 12 points, should his regression match the league's average, considering he has averaged 105 vertical passes per season so far in his career.
Allen's rushing prowess
Allen has quickly proved himself to be one of the game's most productive quarterbacks when running the football, the first in NFL history to score at least eight rushing touchdowns in three consecutive years, doing so in each of his first three NFL seasons. He is, in fact, already second all by himself on the all-time list of such seasons, trailing only Cam Newton's four (2011-12, 2015, 2020).
The problem with this is the fluky nature of quarterbacks' rushing touchdowns, and while Allen enters 2021 very clearly as one of the game's most reliable in this department, he's bound to be bitten by the regression bug one of these years. Last season, seven of his nine scores came on rushing attempts within three yards of the goal line. In two of those games (Weeks 8 and 12), his fantasy output would have actually hurt your fantasy team had the Bills not been in such a position to give him said chances. And in another one (Week 4), he would've dropped from a clear start-worthy effort to an ordinary one. Bear in mind that in only nine of Allen's 16 games did he finish among the top 10 QBs in fantasy points, tied for only third best at the position.
Newton provides a good comparison point for the unpredictable nature of rushing scores: Three times before 2020 he scored at least eight rushing TDs. He once managed at least eight in the subsequent season (2012's eight, coming off his rookie total of 14), and averaged 6.3 in those follow-up campaigns.
To put this another way, Mike Clay's outstanding work estimating expected touchdowns tells another story: Allen's three-year total for expected touchdowns was 19.4, compared to the 25 he actually scored, and he overperformed his expectation in the category in each of those three seasons. Sure, Allen benefits from often being his team's first read at the goal line, but projecting those opportunities year over year is difficult.
What history tells us about Allen-like, dominant fantasy seasons
Again, Allen's 396.06 fantasy points were the fifth most by a quarterback in any season, but the passers who approached or reached the 400-point plateau have a troubling history of follow-up-year regression. Certainly Allen's odds of a repeat -- or improvement -- are greater than anyone in the game's lengthy history, if for no other reason than he's scheduled for an additional game in 2021. On a per-game basis, however, he's highly unlikely to repeat what was a 24.8 average, the seventh best in history by any quarterback with at least 12 games played.
Nine quarterbacks in history have ever scored 300-plus fantasy points -- considered the threshold for a "great" (yet no longer elite) performance in the modern game -- in consecutive seasons: Tom Brady, Drew Brees, Brett Favre, Lamar Jackson, Peyton Manning, Newton, Aaron Rodgers, Deshaun Watson and Russell Wilson. Rodgers and Wilson each had multiple consecutive-season streaks, Brees' streak was six years in a row, one of Rodgers' streaks was four seasons and Manning, Rodgers and Watson each had a three-year streak.
But here's the catch: Only 14 of the 71 quarterbacks in history to score 300 points in a season managed to improve either their seasonal total or their points-per-game mark the following season. Brees, by the way, owns five of those 14 seasons. It's Brees who serves as the best-case comparison for Allen entering 2021, highlighting Brees' 2012-13 performance. In 2012, Brees scored 345.58 fantasy points to lead all QBs, only to improve that total to 357.68 in 2013, a second to record-setting Manning.
The key difference, of course, was that Brees had a deeper receiving corps then than Allen does now, with Marques Colston, Jimmy Graham and Darren Sproles leading the way, in addition to key supporting-cast contributors Lance Moore, Pierre Thomas and Kenny Stills. Stefon Diggs is an excellent No. 1 wide receiver, arguably on par with Colston of that era, but the Bills lack the kind of pass-catching tight end or running back akin to Graham or Sproles, with Dawson Knox at the former position and Devin Singletary and Zack Moss at the latter.
It's history that validates the age-old debate about paying up for the previous season's top quarterback, as the league's leader during the past decade has regressed in total fantasy points scored by a whopping 86.67 points in his follow-up campaign. The group also averaged 1.5 games missed in that subsequent season, so if you'd rather use prorated points per game over a 16-game season, then that group declined by 69.2 points.
That's not to say Allen declining by nearly 70 fantasy points -- and again, it might be closer to 50 at the average historical rate, in a 17-game campaign -- would make him devoid of value. But it'd make him a weak choice as a quarterback selection in the draft's first three rounds, and it's far from outrageous to make a case for any of Mahomes, Kyler Murray or Jackson to outscore him.
Every year, people in ESPN drafts race to get the previous season's highest-scoring quarterback. In the past five years (starting with the most recent), the first QB was selected 11th, 18th, 23rd, 18th and 13th overall. Allen's profile brings statistical variance, and there's no reason to think he's clearly better than the rest of the Mahomes/Murray/Jackson positional top tier. In fact, that there are four quarterbacks with a bona fide chance at a 400-point, 17-game campaign makes it much less mandatory to take one within even the first 40 selections of your draft.
Celebrate the guy's breakout, and enjoy his next steps. But from a fantasy draft perspective, temper your expectations for an Allen repeat.