Since 2015, when Washington head coach Jay Gruden quietly handed play-calling duties to his 29-year-old offensive coordinator, Sean McVay has earned a reputation in football circles as somewhat of a play-calling savant.

Ask those who witnessed his swift ascent through the ranks — from wunderkind assistant to youngest head coach in NFL history with the Rams to potential Coach of the Year candidate — and, inevitably, they’ll mention his memory. When it comes to football, it is borderline photographic.

“He’s like ‘Rain Man,’” says Rams offensive coordinator Matt LaFleur. “He’ll remember plays from before he was born. I’m not joking. I’ve never met somebody with the recall he has.”

Every week, McVay’s gameplan is memorized, each play filed away to be retrieved at a moment’s notice. On Sundays, his double-sided, 11-by-17 play sheet is essentially window dressing, used mostly between drives as a security blanket. Challenge him to recount any of the 306 plays he has called this season, and he is confident he could describe any of them in full detail.

To his assistants, McVay is a bionic playbook, capable of recounting random play sequences from months or years earlier.

“He’s special,” says offensive line coach Aaron Kromer. “He remembers everything.” And that’s not limited to his own team and its opponents. As LaFleur put together a play this preseason, McVay casually referenced a related sequence from a 2015 game between the Broncos and Steelers.

“I’m like, ‘How do you remember that?’” LaFleur says. “He’s just got one of those crazy minds. Everything sticks with him.”

This mastery of the playbook is no doubt a keystone of McVay’s success, like it has been for the dozen or so other NFL coaches who call their team’s offensive plays. But play-calling is more art form than science. A memorized gameplan is useless if the plan itself is thwarted.

“I think it’s the hardest job in all of sports, to be honest with you,” says Chargers head coach Anthony Lynn, hired a day after McVay and quickly handed over play calling duties to his offensive coordinator, Ken Whisenhunt.