Last Thursday, Green Bay Packers quarterback Aaron Rodgers, ahead 14-7 on the New Orleans Saints with just a few seconds left in the first quarter, lined up in the shotgun and saw that Saints defensive coordinator Gregg Williams had called for a pressure look (though not an all-out blitz), coupled with man-to-man coverage on his receivers. Rodgers made a signal for his receivers to run quick routes against their defenders and away from the safeties who remained deep. He called for the snap, and everything seemed to go to plan. His offensive line picked up the blitz and the Saints were in the coverage he expected. Unfortunately, there was one problem: Rodgers’ primary read on the new play, Randall Cobb, a rookie from Kentucky, ran the wrong route. Fortunately, however, Cobb followed the coaching adage that if he was going to make a mistake he’d at least make it at full speed. Although he missed his route, Cobb burst upfield several steps and broke inside on a slant, thereby completely turning around Saints defensive back Roman Harper. Cobb caught a simple pass from Rodgers, juked safety Malcolm Jenkins and leaped over the goal line for his first career touchdown. Rodgers was able to make the play with such little backyard football flexibility because the rest of his thought process against a blitz — when the pressure is most on and offensive and defensive mistakes are magnified — was so disciplined; his identification of the defense and check at the line was so good that even a busted play could go for a touchdown.

Identifying, and developing a quarterback who can play under pressure is a true challenge. As one NFL personnel director told me, while there are 32 starting quarterbacks in the NFL, there aren’t 32 players qualified for their jobs. Throwing motions and mechanics go out the window unless a guy can be accurate under pressure and make great decisions. No one cares how good a quarterback is against air. What matters is: Can he beat the blitz?

Tom Brady and Peyton Manning are quite possibly the greatest anti-blitz quarterbacks in the history of football. And when your team doesn’t have one of those guys — or, in the case of the 2008 Patriots and the 2011 Colts, if they’re injured — you’re not so much worried about whether the backup can run the offense or learn the playbook or even hit the open receiver. You’re worried about third-and-7 in the fourth quarter. How will he handle some convoluted blitz involving three defenders all attacking the same gap while the pass defenders aren’t where he thought they’d be. To succeed under that kind of pressure, you need something more than arm strength, superior height, and even that coveted kind of on-the-fly fluid, athletic intelligence. Instead, you need, well, what is it exactly? What you’re looking for in a quarterback can’t be put into words. It’s some brew of grit, studiousness, and instant pattern recognition that allows the great ones to put their teams in positions to succeed. There is no way to directly evaluate this. The 40-yard dash doesn’t capture it; neither does the Wonderlic. So, instead of spilling more words, let’s look at some examples.

These video clips from last season depict Tom Brady and Peyton Manning defeating blitzes before they even begin. In both examples, the defense shows pressure, along with a few other clues as to its intentions, and each quarterback changes the call. Maybe it was from a bad play into a safe one. Maybe they just knew the perfect call. In the first clip, Tom Brady recognizes that the New York Jets are bringing an all-out blitz, so he changes both the pass play and the pass protection and delivers a catch-and-throw quick strike from the shotgun. In the second clip, Peyton Manning sees that the Miami Dolphins are showing a pressure look (although not an all-out Cover Zero blitz), so he checks to a wide receiver screen, a play popular at the college level but not in the NFL (that has been changing, however, thanks in part to plays like this).

The Brady example combines macrostrategy with microtactics. Generally, the NFL is a game of tactics, not strategy. Most NFL offenses are schematically very similar, which is why they all basically look the same. But the countless hours coaches spend watching tape and meeting with players are not spent idly. Within the league’s apparent uniformity is a cascade of small adjustments — moving a defensive lineman out a few inches to align on an offensive player’s outside eye versus playing him straight up, the speed at which offensive linemen transition from double-teaming opposing linemen to blocking linebackers — that are the difference between a winning game plan and a weak one. NFL coaches, while not always creative when it comes to macrostrategy, specialize in the unseen game. Bill Belichick, however, is one of the rare coaches who isn’t shy about shifting strategies along with his tactical maneuvers. His tweaks include not just changing a player’s alignment but also shifting between two-gap 3-4 defenses and the 4-3 or from power football to a pass-first spread. On this play Belichick and Brady blend both.

The Patriots begin with three receivers in a bunch set to one side, with a running back and a single receiver, Deion Branch, backside. For the strategic portion, the Patriots motion the running back out of the backfield and align in a no-back set. By spreading the field with five receivers who can each attack vertically at the snap (or receive a quick pass and get yards if not immediately covered by a defender), Brady forces the defense to show its hand. The five receivers are covered by man-to-man pass defenders while the other defenders get in position to blitz; the key tell that Brady recognizes is that there is no deep safety. He makes a check at the line that is both common and unique: To the two-receiver side, he calls a simple slant and vertical combination, where the inside receiver’s job is to run straight downfield and also to provide a “rub” for the outside receiver coming underneath. It’s a good choice against man coverage. Then, on the other side, Brady directs all three of the bunch receivers, a group that includes tight ends Aaron Hernandez and Rob Gronkowski, but also the diminutive Wes Welker, to pass protect. Why did he want all three to block?

They were a means to an end. Brady had them block not because he was concerned about that side, but because he wanted to “slide” the protection the other way. By including all three receivers in the protection, the linemen to the other side were free to step out and deal with the overload blitz the Jets were showing to Brady’s left. And, of course, it worked — with the protection and the quick pass combination, plus a good throw and broken tackles, the Patriots scored a backbreaking touchdown.

Peyton Manning’s call against the Dolphins is classic Peyton: A bit frenetic as the clock winds down, lots of presnap gyrations, but the perfect call for the situation. Unlike the Patriots, the Colts rarely get into new or exotic formations, preferring to keep it simple and allow Manning to make decisions on the line. The Colts line up in their most common formation, with two receivers to one side, a receiver and a tight end to the other, and one running back in the backfield. The Dolphins show a pressure look with the inside linebackers, but Manning likely keys in here on a couple of other points. First, unlike the Jets, the Dolphins align with a deep safety. This gives Miami more defensive flexibility, so unlike Brady in the previous clip, Peyton can’t call a quick pass over the middle and know for sure how the defense will react. Second, although the safety is deep, the cornerbacks over his receivers aligned in an “off” position, giving plenty of cushion. Although this meant Manning wouldn’t be able to go deep (the clock was under one minute and the Colts trailed the Dolphins), he saw that he could throw the ball underneath. That made a quick outside pass the best option. But what kind of outside pass?

The third point helps answer our question. Notice the defender in the red box, the defensive end. In this situation, he was a “rush end,” meaning he wasn’t going to be dropping into coverage. More important, he was aligned in a wide technique, and all the linebackers were lined up inside of him. The upshot is that if Manning threw a screen pass, there would be no defender to make a quick stop. That was enough for Manning.

On the play, the inside receiver blocked out on the corner over Pierre Garcon, the outside receiver. The Colts’ offensive tackles “pass set,” meaning they drew the defenders upfield by acting like they were pass protecting. The center and both guards, however, pass set for only a moment before releasing downfield. One of them “kicks out” — seals to the outside — the defensive back who lined up over the slot receiver, while the other lineman seals inside to block the safety. Manning delivers a pass to Garcon, who rumbles for the game-winning touchdown.

This play was often criticized by television commentators because it appears that Garcon catches the ball past the line of scrimmage while one of the linemen is downfield. This misunderstands the rules, but also highlights why screens — particularly receiver screens — are often more useful in college and high school football than the NFL. In college and high school (generally speaking), as long as the pass is thrown behind the line of scrimmage, the ineligible man downfield rule does not apply. This is a major reason why the “jailbreak” screen is so effective, as the linemen can barrel downfield against a hard-charging defense and the play turns into something resembling a kickoff return. In the NFL, on the other hand, the ineligible receiver downfield rule always applies, but linemen are allowed to get one yard downfield. In the Colts play, it doesn’t look to me like any of the linemen were more than a yard downfield. But in either case, there is nothing gimmicky about the play. It’s simply a good call that allowed the linemen to make downfield blocks and put talented players in open territory.

Of course, there is more to being an NFL quarterback than simply checking to a quick slant or receiver screen against the blitz, particularly against the zone blitz and other defensive exotics. But the lesson here is that sometimes the game doesn’t have to be complicated. None of these plays required a rocket arm, but in both instances the pressure was on. Neither Aaron Rodgers nor Tom Brady nor Peyton Manning woke up one day with the ability to make these decisions; it was the gradual synthesis of talent, experience, and studiousness that lets them beat teams by simply tossing the ball to the side and letting their teammates do the rest. There are a lot of arms in the NFL, but not many of them can do that.

Chris Brown runs the website Smart Football . This is his first piece for Grantland. Follow him on Twitter: @smartfootball.

To comment on this story through Facebook, click here.