The big play has always mattered, but in the past few years, NFL games have become battlefields between teams trying to create and prevent explosive plays. Defenses, tormented by quarterbacks like Patrick Mahomes and Josh Allen, have leaned into Vic Fangio-style philosophies and continued to raise their rates of two-high safety looks, funneling teams toward the run and short passes. Teams played two-deep shells more than 45% of the time on early downs in 2025, up from 38% in 2020 and 35% in 2017.