Against the blitz, Allen ranked below league-average in completion percentage (47.4), yards per attempt (6.1 yards) and passer rating (61) in his rookie season -- which made Buffalo's first two games of the 2019 season against two of the league's most aggressive defensive coordinators an opportunity for him to showcase his offseason development.
So far, he's on the right track.
Against the New York Jets on Sunday, Allen completed 8 of 13 passes against the blitz, his lone blemish being an interception off a tipped pass at the line of scrimmage. He also turned in a 107 passer rating with 139 yards and a touchdown and ran for another when the Jets didn't blitz, but recorded at least one pass-rush win during a play.
Beyond his ability to stand strong in the pocket, Allen made smart decisions when forced outside the pocket -- something he did not do as a rookie.
He smartly threw the ball away on the Bills' opening drive when the Jets' pressure collapsed the pocket, then completed a 24-yard pass to Tommy Sweeney on his next rollout. Allen nearly threw a back-breaking interception in the third quarter -- he escaped the pocket but threw an off-balance, all-arm pass to receiver John Brown that Jets safety Marcus Maye broke on and dropped at his own 1-yard line.
But Allen quickly recovered from his mistake. On the game's decisive drive, he rolled out and threw the ball away on second-and-2 before picking up the first down on a designed QB sweep. Later in the drive, he calmly rolled to his right to avoid blitzing safety Jamal Adams on second-and-16, finding Devin Singletary for a 12-yard gain. The next play, Allen delivered the game-winning touchdown to Brown.
Allen's maturation as a passer was a focal point for Buffalo this offseason. The team leaned on Allen and the passing game often in Week 1 and he ultimately rewarded their confidence.
"It goes back to Josh's second year in the system and the continuity that we have," coach Sean McDermott said, "and just the clarity with which I think he operates -- in terms of where he knows his guys are going to be and there's a lot of guys out there that he trusts.
"So, he's not, we're not, again, a finished product but we have to continue to grow that as well and be able to handle those situations, whether it's no-huddle, whether it's taking the checkdowns, whether it's throwing the ball down the field, that's all part of being a complete offense."
His performance against Jets defensive coordinator Gregg Williams should serve as a benchmark when he faces New York Giants defensive coordinator James Bettcher, whose Arizona Cardinals defenses ranked second in the NFL in blitz percentage from 2015-17, and whose Giants finished 11th in the same category last season.
Despite the Giants' aggression (seventh-highest blitz rate in the NFL in Week 1), there exists an opportunity for success against a defense that allowed Dak Prescott to complete 72% of his passes against the blitz last week for 128 yards.
Bills offensive coordinator Brian Daboll said Allen's ability to extend plays from outside the pocket is often "instinctive" and he "never wants to take a player's instinct away," so don't expect Daboll or McDermott to limit how often Allen ventures outside the pocket.
And as Allen scrambles, the rest of the offense adjusts.
"Everybody's got their own scramble rules," Allen said. "You see a quarterback scrambling, you try to run towards him, if there's no one behind you then you run the opposite way. It's nothing too difficult but the plan is to get the ball out quickly and if I have to improvise and make a couple plays on the run and that's what is asked of me to do, then I'm going to try to do that."
Before signing with the Bills in 2017, safety Micah Hyde played for the Green Bay Packers -- who are well-known for improvising quarterback Aaron Rodgers and the secondary route tree his receivers initiate once he leaves the pocket.
Hyde said those scramble rules make life difficult for a secondary.
"First guy to the sideline comes back to the ball. Second, third, fourth [receivers], they go deep pylon," Hyde said. "Make the easiest throw for him -- so if he's scrambling left, the receiver [on that side] runs a comeback and all the other guys go to the deep pylon ... It's kind of tough because in the secondary, you' re trying to latch onto your guy and if he breaks off deep upfield, it's dangerous."
Players who can get open quickly underneath such as Cole Beasley or get behind a secondary such as Brown are tailor-made to thrive when Allen leaves the pocket. As Daboll put it, the scramble route tree's success hinges on receivers staying vigilant.
"It's a whole 'nother element to the game that you have to practice offensively, and I know [opponents] practice defensively," Daboll said.
Perhaps no job is tougher than an offensive lineman's responsibility once a play breaks down. The linemen are already blindly blocking for a particular spot, so their actions once the quarterback scrambles are often reactionary. Especially with Allen, who led all quarterbacks last season in rushing yards per game, linemen have to be ready to improvise along with him.
"Keep my feet hot, because anything can happen on any play with Josh," left tackle Dion Dawkins said. "I just can't allow myself to get comfortable and [need to] keep playing until that whistle is blown."
The onus is on Allen to refine his improvisational play. Leaving the pocket makes life harder for a defense -- but not if Allen only completes 29% of his throws outside the pocket like he did in 2018. With his arm strength and mobility, he knows he can make the big play.
For now, he just needs to make the smart play.
"Really it's just the smartest play is the best play. Especially against a defense that thrives on turnovers," Allen said last week. "They're trying to get pressure to the quarterback. If there's an option to get a back or a receiver quick underneath and make some plays, that's what we're going to try to do. That's the job of the quarterback to get the ball to playmakers and let them make some plays."