Jim Mora’s “Playoffs?! Playoffs?!” rant is, along with other feel-good moments like “They are who we thought they were!” and “Go play intramurals, brother!,” in the pantheon of unhinged postgame outbursts. Resurrected every year just prior to, yes, the playoffs, it sticks with us because in one nasal-inflected word Mora revealed everything about himself at that moment: He was a doomed man, something confirmed just weeks later when he was fired.

Yet the most interesting aspect of the rant is that almost everyone forgets the real target of the coach’s ire. Mora was squarely and publicly laying the blame for his team’s ugly loss to the 49ers at the feet of his team’s young franchise quarterback — some guy named Peyton Manning.

“Do not blame that game on the defense, OK?” said Mora. “When you turn the ball over five times — four interceptions, one for a touchdown, three others in field position to set up touchdowns — you ain’t going to beat anybody.”

Keep in mind that, by 2001, Manning had been to the Pro Bowl twice and had compiled a 23-9 record over the prior two seasons. Still, Mora was unrelenting. “I don’t know who the hell we think we are when we do something like that,” said Mora. “Unbelievable. Pitiful. It’s absolutely pitiful to perform like that.” Although publicly ripping your franchise player is hardly advisable, Mora wasn’t wrong; Manning had played kind of awfully, and his 23 interceptions that season — coupled with the league’s 31st-ranked scoring defense — had gone a long way in sending the Colts to a 6-10 record and ultimately costing Mora his job.

Few remember that Mora was talking about Peyton Manning because Peyton Manning has spent the past 12 years making us forget. Manning has been so good for so long that we can barely remember a time before he and Tom Brady were the game’s best. Mora’s tirade acts as a reminder that not even Manning arrived in the NFL as a fully formed star quarterback. He and Brady had their own struggles early on; the remarkable thing is not where they are now, but how far they’ve come.

Since Mora’s outburst, Manning has become a Super Bowl champion and solidified his status as one of the greatest quarterbacks of all time. He’s closer to the end of his career than the beginning, and before long, he and Brady will be off to sell pizzas or pick Kentucky Derby winners or do whatever else football immortals do when their playing days are over. When they do move on, the spots atop the quarterback hierarchy will be open again, and the question will be who takes up the mantle. Aaron Rodgers looks like a lock for greatness, but the other worthy contenders — from Russell Wilson to Robert Griffin III to Andrew Luck, and even Joe Flacco — are by no means finished products. Each has a long way to go before he can be considered a master of his craft.

No position is more scrutinized — How tall is he? How far can he throw? Who is he dating? — and nowhere in football is greatness valued or debated more, but exactly how young, promising quarterbacks become Tom Brady and Peyton Manning remains something of a mystery. The results are apparent, but most are unversed in the actual process. Manning, Brady, and Rodgers are great because they’ve taken the raw materials of the position — an understanding of defenses, of why receivers get open and how to find them — and transformed them into muscle memory they can use to fluidly perform, every time. Greatness isn’t something quarterbacks stumble upon. It’s something that becomes ingrained into their very constitution.

It’s no secret Peyton Manning works pretty hard. In April, he and his brother Eli, along with their top pass-catching targets, spent time on Duke’s campus with Blue Devils head coach David Cutcliffe, who coached Peyton and Eli in college. At this stage, both brothers have seen their share of football — 2013 will be Eli’s 10th season in the league — but in traveling to Durham, Peyton wanted to go back to the beginning. He asked Cutcliffe for a return to the basics, to “coach us like we were both freshmen at Tennessee or Ole Miss.”

When Cutcliffe trains a young quarterback, he begins with his most valuable asset: his mind. “I do not talk about passing routes with them for one month,” Cutcliffe said at a coaches clinic in 2011. “All we do is teach them defense for a month. We teach them the history of defense. We teach them the history of the zone blitz. We teach them what it is, and what is happening in the defense. Once the quarterback learns coverages, it enables them to move on in the teaching progression.”

In football’s earliest days, the forward pass was primarily about surprising the defense or attacking a single, isolated defender locked in man coverage. As defenses got more sophisticated, offenses evolved too, with the largest contribution coming from former San Diego Chargers head coach Sid Gillman, the “Father of the Passing Game.” Gillman refined passing into a calibrated, organized attack. His insights inform every throw you’ll see this fall.

Realizing that a football field is nothing more than a 53⅓-yard-wide geometric plane, Gillman designed his pass patterns to stretch defenses past their breaking points. His favorite method was to divide the field into five passing lanes and then allocate five receivers horizontally in each one. Against most zones, at least one receiver would be open. Below is an image from one of Gillman’s final playbooks with the Philadelphia Eagles.

Along with stretching defenses left to right and right to left, Gillman also stretched them deep to short, by putting two or three receivers on the same vertical line. With Gillman’s ideas in mind, well-designed pass plays today still combine horizontal or vertical stretches with routes also designed to defeat man coverage. This means that as long as a quarterback can read the defense, he can find an open receiver. That, however, is the trick. As Gillman liked to write in his quarterbacks’ playbooks: “You must know the theory of all coverages. Without this knowledge you are dead.”

A quarterback translates his knowledge of defenses and passing plays to the field through his reads, of which there are two basic types: progression and coverage. “A progression read is a pass play where three or more receivers are looked to in a one, two, three progression. ‘Is he open? Is he open? Is he open?'” Cutcliffe explained at a coaching clinic. With a coverage read, it’s “the coverage played by the defense” that determines which receivers the quarterback looks for.

A few decades ago, simple if-then coverage reads were the most common way to teach a young quarterback how to find an open receiver. If the key defender dropped one way, the quarterback threw the ball to, say, his tight end, but if the defender dropped the other way, the quarterback threw it to the wide receiver. As defenses have become increasingly sophisticated, quarterbacks now need more options than simple key-defender reads provide. The answer was the progression read, which forces a quarterback to look at one receiver after another until he gets to the first open man. The progression read removes the need to look directly at defenders, but it doesn’t mean a quarterback should be looking directly at receivers, either.

“I don’t tell our guys to look at a defender,” Georgia head coach Mark Richt said at a coaching clinic. “If our quarterback is looking at a defender, then his vision is too tight. Let’s say he looks at the Will [weakside] linebacker and the Will linebacker flies out to the flat. If he flies out to the flat, I better hit the slant, right? Well, what if the Mike [middle linebacker] runs that way and picks your slant? It’s because you told him to look at the Will.”

The quarterback isn’t looking for defenders. He’s looking for passing lanes — open windows through which he can throw the ball. “I tell them to look to the area,” said Richt. “You look to the slant area, to the curl area. If there’s nothing between you and him, throw it in there. If there’s someone in the throwing lane, then go to the next read.”

Most modern passing plays may use progressions, but that still leaves open the question of which progression, and the answer is what brings everything together. It’s a coverage read that determines the quarterback’s progression. It was Gillman who developed one of the earliest and most effective tools for this, the idea of the “best-located safety,” which he defined as the “safety which is lined up in a position that is least likely to be able to assist in the coverage of a wide receiver. In other words, he’s the furthest removed and best to attack!” Most NFL teams still use the idea of the best-located safety as a coverage key, but it’s only one of several.

Good passing teams package different pass concepts together to give their quarterbacks answers versus a variety of defenses. The coverage read on a given play is tied to these pass concepts. For example, if the route combination to one side is better against single-safety defenses like Cover Three, and the concept to the other side is better against two-deep, split-safety coverages, then the quarterback’s read will be based on the number of safeties.

Given the byzantine schemes defenses have used in recent years, simple coverage keys aren’t always enough to identify an open receiver. Aside from the usual veteran quarterback tricks — look-offs, dummy signals, and so on — Brady and Manning are better than other quarterbacks because they can process more information. They see not only the number of deep safeties, but the depth and leverage of the cornerbacks and the alignment of the linebackers. They see the entire defensive structure.

This is not to say they always (or even usually) know the exact coverage, but their years of study and practice allow them to make an instant judgment about the basic tactics of a defense — and where it’s weakest. For example, while mounting a furious comeback against the 49ers last season, the Patriots lined up with a different route concept to each side of the formation: a curl/flat concept to Brady’s left and the Levels concept to his right. Curl/flat is a horizontal stretch on the defense that works best against single-safety defenses like Cover Three, whereas Levels is a vertical or high/low stretch that works best against two-safety defenses. New England tied those concepts together with a Seam Read route by Wes Welker, whose job was to either stay up the seam against a single middle safety or split two deep ones.

Brady’s progressions on the play were either (1) Seam Read, (2) curl, and (3) flat; or, if looking the other way, (1) Seam Read, (2) deep square-in, and (3) short square-in. What made his task more difficult is that the 49ers typically use a lot of hybrid defenses, frequently playing different coverages to each side of the field, specifically to confuse a quarterback’s coverage keys.

On this play, the 49ers align in what appears to be Quarter-Quarter-Half coverage, with Cover Four or Quarters to the offense’s left and a type of Two-Deep to its right. Where some quarterbacks may get confused, Brady did not. He knew that the inside safety to his left had to defend Welker’s seam route, and when he did, it transformed the coverage to that side into essentially a single-safety type of coverage, one perfect for the curl/flat combination to Brady’s left. As Brady dropped he confirmed the coverage, saw Welker blanketed, and calmly delivered the ball to Brandon Lloyd on a curl for a first down.

No matter how much he’s prepared, for an NFL quarterback, the moment just after the snap is bedlam. Cornerbacks who looked like they were in soft coverage roll up to press receivers, unexpected blitzers come tearing off the edge, and savvy safeties start on one side of the field only to fly to the other. It’s also the most critical moment. Regardless of what bizarre look the defense showed before the snap, once the play begins, it must reveal its true intentions.

This is why, on their initial steps away from the line — the first step in a three-step drop, or the first three steps in a five-step drop — quarterbacks must keep their eyes directly down the middle of the field and use their peripheral vision to see how the defense, in particular the safeties, rotate and align. Gillman called this “reading the square,” and not only is it crucial for a quarterback’s read, it also provides a natural look-off. The quarterback gives nothing away when he looks deep down the middle. By the end of his drop, the quarterback should grasp enough of his coverage read to decide which progression of receivers he’ll look to. At that point it’s as simple as reading one, two, three — in theory.

The next step is not only making the right read but making it at the right time. Receivers in the NFL are open for only the briefest of moments, and “too often,” according to former 49ers head coach Bill Walsh, “either the quarterback is standing there waiting for the receiver, or the receiver has broken before the quarterback can throw the ball.” Being too early or too late is usually no different from being wrong.

Careful calibration of the timing between quarterbacks and receivers is a fundamental element of making an offense work. By defining a quarterback’s drops by the specific number of steps taken, offenses can synchronize the quarterback’s movements with the routes of the receivers; the timing between when a quarterback is ready to throw and when the receiver is ready to receive the ball must be perfect. Specifically, the quarterback’s first read should be thrown to when his last step hits the ground. This is what is known as a “rhythm” throw.

Now, let’s say the quarterback’s first read isn’t open. How does he know when to move to the next receiver? The idea of finding a secondary receiver leaves some quarterbacks looking like they just lost their wallet. For others, like Brady or Manning, it looks easy, and it’s because it’s not only their brains telling them when to look.

“His feet are telling him when to move to no. 2 and no. 3,” current San Francisco head coach Jim Harbaugh said to a room full of quarterback coaches back when he was coaching at the University of San Diego. “One-two-three-four-five-plant — throw it. If it’s not there, first hitch is to the [second read], and then the second hitch is to [third read].”

This must be precise. “If you have a passing system where he’s dropping back and waiting for a guy to come open, a lot of bad stuff is going to happen,” said Harbaugh. When Brady hits the last step of his drop in the play from earlier, he’s in perfect position to throw the rhythm seam to Welker — except Welker isn’t open. He then calmly bounces in place, resetting his feet while remaining in perfect balance, and throws a strike.

Often, we associate being great with being spectacular, but that’s the secret about playing quarterback — great quarterbacks seek the banality of perfection. It’s about avoiding the bad play, hitting the right receiver, making the right read, and throwing an accurate pass, every time. Mora was absolutely right when he said you simply cannot win if your quarterback makes critical mistakes.

The process of becoming that player is only so complex. Defenses, reads, and coverages can all be learned in time. It just takes a truly dedicated player with a disciplined mind to see that process to its end. Played out as far as it will go, those decisions and movements are no longer conscious ones. For the best quarterbacks, it goes beyond making the right read and correct progression. The elements of great quarterbacking become a part of their very makeup as players. According to Bill Walsh, “because of the dynamic role he plays on the team, a quarterback must have physical, mental, emotional and instinctive traits that go well beyond the mere ability to pass a football.” If the league’s young quarterbacks want to be truly great, they’ll have to master something that comes from the combination of all those traits, something that can’t really be coached, something Brady and Manning have both done for years.

“Does he make everyone around him better?” Duke’s Cutcliffe asked rhetorically in 2011. “We have all played with those types of quarterbacks, we have coached them, or we have seen them. That is the greatest gift the quarterback can have.”