It's no secret that play-action passing was a hallmark of both Peyton Manning's time in Indianapolis as well as Andrew Luck's time at Stanford. In both situations the key was to pull a guard in order to sell the run fake:
Just think about what kind of effect that has on the defense. While both players were impressive in their play-action fakes — and someone like Peyton Manning is even more impressive — if you’re a linebacker or safety and you see a pulling guard, you basically can’t help but tell yourself: “It’s a run.” Especially since run plays that involve a pulling guard means one thing: “power,” in the lowercase sense of lots of bodies will be at the point of attack so the defense needs to match numbers as well. And in the case of both Stanford and Baylor it also means “power” in another sense: the “Power-O” play where the linemen block down and a backside guard pulls to lead. Stanford, being a more of a pro-style offense, runs the traditional Power-O numerous times every game. Baylor, being a spread team, typically used the vaunted “inverted veer” play, which is the spread offense’s read-based adaptation of the old Power-O. Regardless, for opponents of both, a pulling guard meant trouble for Stanford’s and Baylor’s opponents run defenses, which, through the use of play-action, in turn meant trouble for their pass defense. That Bill Walsh guy just might have been onto something.