If general manager Brandon Beane's gamble to deal the No. 12 pick and two second-round selections for Allen in his first draft as general manager pays off, Allen's ideal size and off-the-charts arm strength will make him the Bills' best quarterback since Jim Kelly retired in 1997.
For a team that has burned through 16 different starting quarterbacks since Kelly, why has it taken this long for the Bills to potentially find their long-term answer at the position?
Let's take a walk through history to find out:
Trading for Rob Johnson in 1998: After starting Todd Collins for 13 games in 1997 and stumbling to a 6-10 record, the Bills dealt their 1998 first- and fourth-round picks to the Jacksonville Jaguars for Johnson. Starting parts of the next four seasons, Johnson went 9-17 for Buffalo. The Jaguars used the No. 9 overall pick in 1998 on running back Fred Taylor, but the Bills probably would not have found a franchise quarterback in that draft. The best they could have done was Brian Griese (No. 91) or Matt Hasselbeck (No. 187).
Missing on Tom Brady in 2000: OK, this one probably is not fair. There were 29 teams besides the Bills that passed on Brady, and the Patriots picked six players before taking a flier on Brady. But history in the AFC East might have been different had the Bills made that choice instead.
Missing on Drew Brees in 2001: This would have been a more realistic selection for the Bills, who traded down from No. 14 to No. 21 in the first round and took cornerback Nate Clements. Brees went 11 picks later to the San Diego Chargers. Barring an injury, Brees will become the NFL's all-time leading passer this season.
Trading for Drew Bledsoe in 2002: After Johnson flopped, the Bills tried their luck in the veteran quarterback market again after a 3-13 season in 2001. Buffalo sent its first-round pick in 2003 to division rival New England for Bledsoe, who had lost his job to Brady. Bledsoe set a franchise record with 4,359 passing yards in 2002, second-most in the NFL that year, but the success was short-lived. Bledsoe ranked 18th in passing yards the next two seasons before being released. Luckily for Buffalo, the first-round pick (No. 14) in 2003 would not have yielded a franchise quarterback.
Trading up to draft J.P. Losman in 2004: The Bills finished with a 6-10 record in 2003, placing them 13th in the 2004 draft and out of reach for top quarterbacks Eli Manning, Philip Rivers and Ben Roethlisberger. The Bills selected wide receiver Lee Evans with their first pick, but with Bledsoe in apparent decline, Buffalo traded its 2005 first-round pick and 2004 second- and fifth-round picks to the Dallas Cowboys to select Losman at No. 22. In his only full season as the starter in 2006, Losman passed for 3,051 yards but proved too turnover-prone.
Missing on Aaron Rodgers in 2005: The Bills gave up the No. 20 overall pick in 2005 in their deal with the Cowboys for Losman, which would have been a perfect spot for Buffalo to catch the draft-day fall of Rodgers. He went No. 24 to the Green Bay Packers.
Drafting Trent Edwards in 2007: It was not as if Edwards, a third-round pick, was projected to become a star. But the Bills started him in 32 games over four seasons, which was more than a casual flirtation. Known as "Captain Checkdown" to Bills fans, Edwards averaged 6.5 yards per pass attempt before being released.
Missing on Joe Flacco in 2008: After starting Edwards and Losman in 2007, the Bills decided to take cornerback Leodis McKelvin with the No. 11 pick in 2008. Joe Flacco went No. 18 to the Baltimore Ravens. Elite or not, Flacco has won a Super Bowl and has eight 3,000-yard passing seasons. His 35,780 career passing yards would have passed Kelly's 35,467 last season as the franchise record.
Missing on Russell Wilson and Kirk Cousins in 2012: Similar to Brady, every NFL team passed on Wilson (third round) and Cousins (fourth round) before they were eventually drafted. The Bills were not in a rush to add a quarterback after giving Ryan Fitzpatrick a six-year, $59 million extension after a 4-2 start in 2011. Fitzpatrick, who supplanted Edwards as the starter in 2010, threw for 3,832 yards and 24 touchdowns in 2011.
Drafting EJ Manuel in 2013: After the Bills lost eight of their final nine games in 2011 and went 6-10 in 2012, the Fitzpatrick era ended when he was released early in 2013. That put the Bills in a desperate spot to draft a quarterback in 2013, which became perhaps the worst class at the position in recent NFL history. Manuel, whom some analysts projected as a mid-round pick, was the Bills' choice at No. 16. He lasted four games into his second season before being benched.
Missing on Jimmy Garoppolo in 2014: General manager Doug Whaley dealt his 2015 first-round pick to trade up from No. 9 to No. 4 in the 2014 draft, selecting wide receiver Sammy Watkins. Whaley believed Manuel needed help around him -- not competition behind him at quarterback -- in order to succeed after a shaky rookie season. That philosophy meant taking offensive tackle Cyrus Kouandjio in the second round in 2014 and passing on Garoppolo, who went No. 62 to the Patriots. Kouandjio, who never became a full-time starter, was released in 2017 weeks after a bizarre encounter with police. Garoppolo became the highest-paid player in NFL history this year.
Passing on Deshaun Watson in 2017: In an awkward transition period in which first-year coach Sean McDermott and soon-to-be-fired general manager Doug Whaley led the Bills' draft, Buffalo traded out of the No. 10 pick, which the Kansas City Chiefs used on quarterback Patrick Mahomes. The Houston Texans took Watson two picks later. The Bills turned the picks they acquired from the Chiefs into cornerback Tre'Davious White and linebacker Tremaine Edmunds, but they might have passed on a potential franchise quarterback in Watson in the process. If Allen pans out for the Bills, the decision will not be second-guessed.