When Green Bay Packers head coach Mike McCarthy began his first NFL job in 1993, as a Kansas City Chiefs offensive assistant working with quarterbacks, he immediately inherited a rather tricky assignment: coaching Joe Montana.

McCarthy had gone to K.C. to work with his mentor Paul Hackett, the Chiefs’ new offensive coordinator and a former assistant for Bill Walsh’s San Francisco 49ers. While working together at the University of Pittsburgh, Hackett and McCarthy had installed a version of Walsh’s legendary West Coast offense, which had powered four Super Bowl titles in the 1980s. McCarthy became enamored of the system during those years with the Panthers, immersing himself in the offense that was taking over football. By the time he went to the Chiefs, McCarthy felt he was ready for any challenge.

Well, almost any challenge: Prior to the 1993 season, the Chiefs traded for Montana, the veteran quarterback with extensive West Coast offense experience and four Super Bowl titles, and the man Jerry Rice referred to as “God.” McCarthy told Milwaukee’s Journal Sentinel that the gravity of the assignment didn’t register until he excitedly let some of his close friends know that he’d be coaching Montana, and one responded by asking, “What in the [expletive] are you going to teach Joe Montana?” It was a good question, and it led McCarthy to become as much Montana’s student as his teacher, soaking in all the knowledge he could from the future Hall of Famer.

More than 20 years later, on the brink of a divisional-round playoff game against the Dallas Cowboys, McCarthy again finds himself in a teacher-student partnership with an elite pupil: Packers quarterback Aaron Rodgers. Though McCarthy is facing a similar challenge of figuring out how to help one of the game’s best quarterbacks get even better, his relationship with Rodgers is far more collaborative than his pairing with Montana ever was, allowing coach and quarterback to try to improve themselves, each other, and the very offense Walsh taught Montana so long ago.

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At some point, the story of every great quarterback morphs from anecdote to myth, and Rodgers’s narrative fits the mold. Barely recruited out of high school, Rodgers wound up at Butte Community College, where Cal coach Jeff Tedford (while scouting a tight end) noticed a skinny QB running around making accurate throws, and offered him a spot with the Golden Bears.

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More on the Super Bowl Under Tedford’s tutelage, Rodgers vaulted from unknown passer to surefire first-rounder, wowing pro scouts by tying an NCAA record with 23 consecutive completions to start a game in a near road upset of top-ranked Southern Cal, a team loaded with future NFL stars (and coached by some guy named Pete Carroll). Rodgers looked like the potential first overall pick, but he fell to no. 24, where the Packers selected him as Brett Favre’s heir apparent. Favre, of course, was uninterested in mentoring his replacement, famously telling ESPN, “My contract doesn’t say I have to get Aaron Rodgers ready to play … I’m not obligated one bit to help anyone.”

It was an inauspicious start for a young quarterback, but Rodgers credits his early years as being crucial to his development. Though the player Rodgers is today stems primarily from his talent and work ethic, being a successful NFL quarterback requires luck as well as skill, and being lucky usually means getting to work with the right people. When the Packers fired Mike Sherman and hired McCarthy as head coach after Rodgers’s first season, it altered the direction of both McCarthy’s and Rodgers’s careers.

McCarthy was hardly a slam dunk hire, having coached relatively pedestrian offenses in New Orleans from 2000 to 2004, and having spent the 2005 season as offensive coordinator for the 49ers, a 4-12 team that finished a woeful 30th in the league in scoring and 32nd in total yards. But Packers general manager Ted Thompson brought in McCarthy hoping the coach’s deep knowledge of the West Coast offense and renowned touch with quarterbacks would tame Favre after a 29-interception season, while also developing Favre’s anointed replacement. Though Favre bounced back under McCarthy, throwing for 4,155 yards, 28 touchdowns, and only 15 interceptions in 2007 en route to the NFC title game, he began to threaten retirement, and by 2008 Thompson and the organization were ready to switch to Rodgers, convinced after witnessing his dramatic improvement that the QB had the makings of a future star.

Since his days as an assistant under Hackett at Pitt, McCarthy has run a “QB school” every offseason, where, away from the pressure of preparing for a weekly opponent, McCarthy can teach his quarterbacks the finer points of the position. In addition to extensive drill work, McCarthy often gives his quarterbacks lengthy written tests, once (according to the Sentinel) even asking his non-Montana quarterbacks in Kansas City to write an essay describing the Chiefs’ version of the West Coast offense “from a philosophical perspective.”

Rodgers has clearly benefited from McCarthy’s training. As good of a prospect as Rodgers was coming out of Cal, it’s striking how different he looks now: he’s more athletic, more natural, and has a stronger arm. While primary credit goes to the long hours Rodgers spends developing his craft on his own, McCarthy provided a structure for that process.

Specifically, when Rodgers arrived in the NFL, there was what McCarthy has labeled a “stiffness” to his game. Under McCarthy’s tutelage, that has since melted away to reveal the fluid, smooth quarterback we see today. Tedford, Rodgers’s college coach and a current CFL head man, is an excellent quarterback teacher, but his college passers tended to be a bit robotic: They all dropped back, held the ball, and released it the same way. That made sense for raw high school and junior college passers who had to quickly learn the fine points of quarterbacking in order to execute Tedford’s pro-style attack, but great NFL passers must make their fundamentals serve them, not the other way around.

The most obvious example of Rodgers making this shift is that he used to hold the ball up near his ear while in the pocket on the theory that it cut down on the time he had to bring the ball back before throwing it forward. Under McCarthy and Packers quarterback coach/offensive coordinator Tom Clements, however, Rodgers gradually began holding the ball between the middle of his chest and his throwing shoulder, a more natural spot that keeps his throwing motion compact while allowing him to rotate his body just enough to create extra velocity.

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More subtly, Rodgers has improved his accuracy, which might sound crazy when discussing a guy who once completed 23 passes in a row in college. But in the NFL, accuracy must be an every-snap thing, particularly in the West Coast offense. Walsh used to jump all over Montana and Steve Young if they missed the precise spot he wanted on a given play — the upper right corner of a receiver’s jersey, a receiver’s left eye, etc. For Rodgers, the key to improved accuracy was perfecting his footwork. “Learning to time up my drop with each route has been a big thing with me,” Rodgers told ESPN The Magazine in 2011. That didn’t just mean opting for a three-step drop versus a five-step drop, but instead learning that while a hitch route might require a three-step drop with one big and two quick steps, a slant route might benefit from three big steps. Rodgers said that mastering those nuances for every conceivable route allows him “to throw the ball in rhythm and hit the same release point with every throw, meaning that no matter what else is happening, the ball comes out on a similar plane. That’s when accuracy comes.”

Indeed, Rodgers is the most visceral of today’s great quarterbacks, oscillating effortlessly between quick timing passes and lasers thrown while on the move after being flushed from the pocket. He often reminds me less of a traditional quarterback than of a great jump shooter in basketball who can hit a shot falling sideways and out of bounds because he always maintains perfect upper-body form. But the real fun comes from watching Rodgers operate the Packers’ modernized West Coast offense, a system perfectly tailored to his quick release and even quicker mind.

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The offense Rodgers operates in Green Bay is based on the same ideas, concepts, and even specific plays that Hackett, McCarthy, and Montana used in Kansas City and that Montana and Hackett had run with the 49ers, all of which is rooted in Walsh’s West Coast offense. While most people think of short timing passes when they hear the term “West Coast offense,” Walsh’s coaching tree — and the coaching tree of his coaching tree — is so long because his insights extended beyond well-designed pass plays to encompass a uniquely thorough, detailed approach to game planning, analyzing defensive weaknesses, and teaching and developing players. Those precepts are Walsh’s true legacy, and they now fuel the Packers’ offensive success.

In McCarthy’s early years, he immersed himself in Walsh’s ideas and language — 22 Z-In, 2 Jet X-Sluggo Seam, and so on. But rather than adhering religiously to those lessons, McCarthy and Rodgers have crafted a version of Walsh’s offense that constantly evolves to keep pace with a changing game. Quoting former Chiefs assistant Jimmy Raye, McCarthy once told USA Today: “‘Football is a cycle. You’re going to see things in this league or out of this league and in college football.’ It’s very important to stay on the front side of that cycle.” The Packers’ offense may be rooted in the playbook McCarthy learned from Hackett 20-plus years ago, but it works because he and Rodgers have subtly blended in new-school tactics.

While the West Coast offense dominated the NFL in the 1990s and early 2000s, it has increasingly fallen out of favor because its emphasis on precision and preparation has too often translated into inflexibility and needless complexity. The traditional West Coast offense features a seemingly countless number of plays — former Packers coach Mike Holmgren once said his playbook contained at least 1,500 plays — because on each play each player had a specific job, such as running a post or a slant. As a result, the only way to take advantage of a shifting, evolving defense was to add yet another new play and hope to call it at the right time, in what amounted to an impossibly hard game of rock-paper-scissors.

That’s not a feasible approach against modern, malleable defenses, and with Rodgers under center, it’s also not necessary. For example, one of the Packers’ most productive pass plays is “three verticals,” in which Green Bay’s receivers have the option to change their routes based on the coverage, trusting Rodgers to see their adjustments in real time.

Chris B. Brown

On this play against the Panthers, both outside receivers, Jordy Nelson and Davante Adams, can run either straight down the field on “go” routes (as Nelson does to Rodgers’s right) or stop after 12 to 15 yards if the defender is playing soft coverage (as Adams does to Rodgers’s left). Meanwhile, the slot receiver, Randall Cobb, runs a “middle read”: If the defense plays with two safeties deep, Cobb will split the safeties and run deep down the middle, but if there’s a deep middle safety like on this play, he’ll turn his route into a square-in and break across the field into Rodgers’s vision.

While this play, which the Packers run over and over again, requires Rodgers and his receivers to all be on the same page — and requires Rodgers to process all of this information and make an accurate throw in fractions of a second — it also replaces as many as 10 different plays from the traditional West Coast offense.

This idea of multiple concepts within each play flows through Green Bay’s offense. Under Favre and in Rodgers’s early seasons, this typically meant combining multiple pass concepts within the same play and letting the QB pick the side based on the defense. More recently, however, the Packers have made extensive use of “packaged plays,” which combine run blocking from the offensive line with screens or downfield passes by the receivers, while the QB has the option to hand off to a running back or throw downfield.

Under McCarthy, Green Bay was among the first NFL teams to begin using packaged plays, which first began bubbling up in college football roughly five years ago. (McCarthy has several friends coaching college on whom he leans for new ideas, including Kevin Sumlin, the forward-thinking coach at Texas A&M.) The above inside zone running play married to quick “pop” or seam routes by the slot receivers is straight from college football, and is a simple way to keep defenses honest if they try to crash down on Eddie Lacy and Green Bay’s increasingly productive run game. It’s also a way for the Packers to use Rodgers’s quick decision-making ability without putting him in harm’s way.

But the Packers’ success doesn’t stem solely from their ability to embrace the latest and greatest; while Green Bay excels at innovating, it’s also better than any other NFL team at executing many of the same plays Walsh used with Montana, most notably the slant pass. Hard as it is to believe, few NFL teams consistently throw the quick slant anymore, as most have replaced it with skinny posts or quick square-ins, or stopped bothering altogether. Put on a Packers game, though, and it can feel like watching old 49ers game film.

It’s not uncommon for Rodgers to complete five to 10 slant passes in a game — he likes them against soft coverage because they give him easy access, and he loves them against the blitz. When New England tried to bring pressure on Rodgers late in the half, he checked into a basic slant to Nelson and, 45 yards later, Green Bay had scored.

The most famous Joe Montana anecdote so perfectly meshes with his reputation as “Joe Cool” that it seems more written than real: Standing around during a TV timeout, with the ball on the 49ers’ own 8-yard line and his team down three points to the Cincinnati Bengals in Super Bowl XXIII, Montana saw that his teammates, including lineman Harris Barton, had tensed up. Then, out of the corner of his eye, he spotted something else. “There, in the stands,” he said to Barton. “Isn’t that John Candy?” His teammates immediately relaxed, Montana marched them down the field for the game-winning touchdown, and his legend grew. Great quarterbacks come in different flavors, but the preternaturally relaxed field general is an archetype as old as football itself.

Rodgers is a few Super Bowls shy of earning direct comparisons to Montana, but — particularly compared to Peyton Manning’s manic nerdiness and Tom Brady’s newfound love of high fives, head butts, and F-bombs — he’s the closest thing we have to a modern-day Joe Cool: This season alone, Rodgers pointedly told Packers fans to R-E-L-A-X after a loss and, on one of the most remarkable plays I’ve ever seen, calmly threw a game-winning touchdown pass without even bothering to buckle his chin strap.

MT @TeeSmallz: @AndrewSiciliano Didn't even buckle his chin strap to throw the game winning TD. pic.twitter.com/fGV89g6xNz — Andrew Siciliano (@AndrewSiciliano) October 12, 2014

By all accounts, Rodgers has always been this way. At a coaching clinic in 2011, Tedford recalled that, before the aforementioned crucial game against USC, Rodgers “was just walking around in the locker room with a smile on his face and getting [his teammates] going, but also getting them relaxed. He was not going haywire and yelling and screaming. He had this confidence about himself, and his leadership ability was unbelievable.”

Of course, similarities in demeanor between Rodgers and Montana wouldn’t matter if the two weren’t also so similar on the field. “When I think about fundamental quarterback play, I think of Aaron and Joe Montana,” McCarthy told the Sentinel. “The productivity is obviously there, but just the way they play the position — their footwork, the balance, the athletic ability, the accuracy of the football, the vision.” I see it too. Montana’s gifts were his accuracy, his decision-making, and his feet, and Rodgers boasts those same attributes — plus a stronger arm.

Rodgers’s talent, drive, and approach to mastering the hardest position in sports have gotten him to this point, but so has his collaboration with McCarthy. Together, coach and QB are on the cusp of winning their second Super Bowl. They’ve already taken the Packers, the old West Coast offense, and the quarterback position into the modern age.