Its elements are simple—grip, drop, setup, throw—but how they blend together into a signature technique is what separates a merely good quarterback from an alltime master

The explanation is stuck somewhere between Philip Rivers's brain and his mouth, instinct once again failing to find words. Rivers is standing in the middle of a grass practice field at Chargers headquarters, gesturing with a football gripped in his right hand. It is an autumn afternoon, breezy and clear in Southern California, 48 hours before Sunday's kickoff.

All of Rivers's teammates are gone, and he's 20 minutes deep into a description of what is required to throw an accurate pass in an NFL game. He has talked meticulously as he pantomimed his routine, from snap to grip to drop-back to setup. He has demonstrated his wacky shoulder-push delivery—the result, he says, of throwing regulation-sized footballs with tiny hands at age six while watching practices of the high school team his father coached in Athens, Ala.—and now he has reached the point at which he releases the ball.

So Rivers is asked: How does he know where the pass will go, and how does he ensure it goes there? And here is the pause. Rivers wiggles the ball in his right hand, fingers across the laces as if ready to throw. He purses his lips, because this isn't easy to articulate. "You always want to pick a target," he says. "Like the chin [of the receiver]. But on some routes I'm throwing at the back of the helmet. A lot of it is just a natural feel."

Rivers strides forward with his left leg, brings the ball up to his right ear and then pauses in midthrow. "There are times," he says, "when I'm seeing how I'm going to throw it as I'm moving my arm. There's a lot happening at the time. Exactly where you're going to put it is still being determined."

Even as it's leaving the fingertips? More head-shaking and silence. Finally: "I don't know," says Rivers. "Like I said, there's a lot going on."

The forward pass is, along with the pitch, the most significant game action in American sport. Made legal in the rules of football just after the turn of the last century (while historians continue to debate its origins, they all agree that the first completion was not from Notre Dame's Gus Dorias to Knute Rockne in 1913, as suggested in cinema, and that it was probably some seven years earlier), it is the centerpiece of the most popular sport in the country, the play that determines the direction and outcome of most games and makes the NFL quarterback the most important of all team athletes.

Pro football has evolved from a run-based to a pass-based game. In 1977, the last year before rules changes that limited contact by defensive backs and vastly expanded receivers' freedom, teams averaged 37.4 running plays and 25.0 passing plays while completing just 51.3% of their passes. In 2009 teams ran the ball just 27.5 plays per game and threw passes on 33.3 plays, while completing 60.9% of passes. The number of passes per game was up to 34.0 through the first eight weeks of the 2010 season. The change has been steady and distinct.

But the act of passing itself is far more resistant to quantification. It is just as much art as science, because its lab is a kinetic (and dangerous) environment. "Early in my career I spent a lot of time studying," says former NFL quarterback Trent Green. "Then [coach] Norv Turner explained to me, your main priority has to be finding a way to do your job even though you're going to get hit right after you do it. Making a throw accurately and repeatedly despite getting blown up, that's what separates great guys from good guys."

From 1992 to '95 Steve Mariucci was the Packers' quarterbacks coach under Mike Holmgren; their chief pupil at the time was Brett Favre. "I had spent a lot of time drilling quarterbacks on fundamentals," says Mariucci, now an analyst with the NFL Network. "Drop back five [steps], hitch and throw. So my first year, Mike tells me to chart how often we actually throw that way, right on rhythm. At the end of the year I came to him and said, 'Mike, it was only 24 percent.' And Mike says to me, 'That's pretty good. My last year at San Francisco it was only 19 percent.' The point is, that fundamental throw, like the pitcher throwing off the mound or a golfer hitting a nine-iron, it just doesn't happen all that often. There has to be a variety of ways of getting the ball to the target."

As Rivers said, there's a lot going on.

Practitioners of the pass are connected by an appreciation of its ineffable nature. Hall of Fame quarterback Dan Fouts recalls when he was a Chargers rookie, in 1973, and 40-year-old Johnny Unitas was his teammate, entering his 18th and final NFL season. "I remember playing catch with him in training camp," says Fouts. "I was just marveling at what I was seeing out of this 40-year-old man. Every throw had a purpose. Not necessarily heat, but intensity. Rhythm was perfect. Follow-through was perfect. That was a training film."

Terry Bradshaw, who had one of the strongest arms in NFL history, says at least one of his peers had more horsepower. "Dan Pastorini," says Bradshaw, citing the '70s gunslinger who twice took Bum Phillips's Oilers to the playoffs but threw 58 more interceptions than touchdowns in his 12-year career. "Dan could throw it 80 yards on a rope." (The merits of this talent, on its own, are questionable.)

Almost everybody agrees that the most precise passer in history was pot-bellied, 5'11", 202-pound sidearm slinger Sonny Jurgensen, who played for the Eagles and the Redskins from 1957 to '74. Respected modern-day quarterback guru Steve Clarkson, who has schooled dozens of major college and NFL passers, will go back even further and argue that Sammy Baugh, who played from 1937 to '52 (and in 1945 completed 70.3% of his passes, when the average quarterback connected on 45.6%), was a truly great passer even by modern standards.

"Accuracy at a certain level cannot be taught," says Hall of Fame quarterback Steve Young. "It's something where your fingertips are directly connected to your brain. Your mind tells you where to send the ball, and your arm follows. There are a lot of guys—a lot of guys—who can watch tape and see what kind of throw they have to make. But they can't actually make that throw, because it's just not their gift. They can rep themselves to be better and play at a high level. But they can't make that throw."

That throw comes together in pieces. And everyone's pieces are a little different.

THE GRIP

Texans quarterback Matt Schaub holds a football in his right hand, standing at the side of the team's practice fields. The point of the ball is cupped between his thumb and index finger, his middle finger rests against the end of the laces, and his ring finger and pinkie reach across the laces. "That was my grip in high school," says Schaub, a seven-year NFL veteran. "Then I got to college [at Virginia] and the ball was different, so I tilted my hand just a little bit." That left Schaub with just his ring finger directly on the laces, and both his middle finger and pinkie touching the laces, but not across them. Rivers's grip is identical, and theirs is the grip that the majority of NFL quarterbacks use.

The fingertip of the throwing hand, as in baseball, is the last point of contact with the ball. "That fingertip produces the spiral," says former Giants coach Jim Fassel, who was also an NFL quarterbacks coach and offensive coordinator. On the release the throwing thumb is ideally driven down to the opposite thigh and the palm turned outward and down. The spiral is the goal, although not all quarterbacks throw a high percentage of spirals—the Colts' Peyton Manning, notably, does not. And not all of them hold the ball like Schaub.

Bradshaw, who led the Steelers to four Super Bowl titles from the 1974 to '79 seasons, put the index finger of his throwing hand close to the point of the ball. "Honestly, there wasn't an off-season that I didn't try to break the habit of holding the ball the way I did," says Bradshaw, now a Fox studio host. "I think I did it that way because I was a javelin thrower [in high school], and you put your finger down toward the end of the javelin. With that index finger down there, I could really make it whistle. But I wasn't very accurate.

But the game was different. Today they all throw 60 percent completions; we ran [the ball] and threw deep."

Troy Aikman, another Hall of Fame quarterback and winner of three Super Bowls from 1992 to '95 with the Cowboys, nearly ignored the laces—he placed the top of his palm across the laces and his fingertips on bare leather. Schaub, meanwhile, licks his fingers incessantly to improve his grip, as does the Saints' Drew Brees. Rivers used to do the same thing. "But I felt like I was eating fertilizer," he says. "Now I'm a spitter. I do it even on the sideline when we're on defense. I just like to feel that little grippiness on my fingertips."

THE SETUP

As the quarterback pulls away from the center, he seeks an economy of movement. "Stay connected," says former NFL quarterback and longtime tutor Zeke Bratkowski. "By that I mean, keep everything tight, close to your chest. Not a lot of extra movement." Packers quarterback Aaron Rodgers is tight. "He's so compact, I love to watch him throw," says Rivers. Brees is tight. Joe Montana was the tightest of all. "Like a ballerina," says Holmgren, who coached Montana with San Francisco. "The way he moved backward was so smooth."

Turner, who was Aikman's offensive coordinator for two Super Bowl seasons in Dallas, says Aikman "would separate from the center quicker than anyone I've ever been around, and still get set and get the ball out of his hands and make the throws."

But not every successful quarterback has that classic setup. One of the NFL's iconic images is that of Joe Namath, drifting back with the ball waist-high in his right hand, then suddenly, ever so briefly, smacking it with his left hand as he brought it upward—almost as a trigger mechanism—before ripping it downfield. "Pulled it up and snapped it off his ear," says Bradshaw. "It was the coolest thing you could ever see."

Most similar to Namath was Dan Marino, who usually carried the ball away from the center with two hands. Just before delivery he'd drop his left hand off the ball and then, much like Namath, pat it again before throwing, as Clarkson describes, "off his right armpit." Don Shula, the Hall of Fame Dolphins coach who brought Marino into the NFL, says, "At one time in the league there was a drill where you would have the quarterbacks get down on one knee, hold the ball over their heads then just throw from that position. That drill was worthless for Dan, because he dropped the ball so low. But he got rid of it so quickly from there."

THE THROW

The quarterback's movement shifts dramatically at the back of his drop, like a car shifting from reverse to drive. His back foot hits and plants, and he strides forward—or hitches—while moving the ball into position; the reads are finalized and the throw is made. "At that point," says Schaub, "everything works from the ground up." Like a golfer or a baseball batter, a quarterback generates torque with his lower body, from the feet up through the hips and only then into the upper body.

"That starts with the way you plant your left foot," says Fassel. "The natural thing is to land on the ball of your foot, but that tends to make your left leg stiff, and that's what we call an antagonistic movement. Instead, you want to land on the heel of your left foot and bend the left knee." Steelers backup Byron Leftwich is a classic stiff-left-leg thrower, which might contribute to his problems with both accuracy and injury.

Clarkson says no quarterback in history used his lower body more decisively in the throwing motion than Hall of Famer John Elway. "John was not only a great athlete, but he was also pigeon-toed, and that helped create a very tight motion that was consistent," says Clarkson. "And where you see a lot of guys carry the ball in the middle of their chest, John carried it in a position where he was ready to throw immediately."

Montana would reach deep into the pocket on the last part of his drop, setting up an almost exaggerated hitch forward, which he used to finish his reads. "Joe's motion from that point forward was almost perfect and very consistent," says Sam Wyche, who coached Montana under Bill Walsh with the 49ers. "And he could reproduce the same mechanics on the run, going left or right."

While Mariucci was coaching at Green Bay, he received a letter from an irate Packers fan named Ken Cote, demanding that Favre become more effective when flushed from the pocket. Mariucci was already using a series of practice plays in which Favre would have to escape left or right and either complete a pass or throw the ball away. He renamed the exercises the Ken Cote Drill, and it is still called that by teams that use it today.

For a righthander, the arm position at delivery ranges from nine o'clock (Jurgensen, often) to noon. Unitas threw at high noon, as does Manning. "Peyton's motion is not great," says Clarkson, "but he's so advanced intellectually that it overcomes any mechanical difficulties." Brees throws three quarters, and at the back of his delivery, he turns his left palm directly away from the target before snapping his body forward. Patriots star Tom Brady is about 11 o'clock. Rivers says he's 10 o'clock, but he gets there differently, dragging the ball out to the side of his body, rather than from behind his ear. During his apprenticeship with the Cowboys from 2003 to '05, Tony Romo would practice throwing from all manner of odd angles, trying to prepare himself to use varied release points during games.

Like deliveries, throwing mechanics are varied. Brady stands tall, with a wide base and a short stride. Rams and Cardinals standout Kurt Warner, says former NFL coordinator and quarterbacks coach Larry Kennan, "threw more effortlessly than anyone I ever saw. Incredible mechanics. He always just looked like he was playing catch, but he could make every throw." Former Ravens coach Brian Billick describes Warren Moon, whom he coached as a coordinator with Vikings in the '90s, in similar terms. "On most of his passes," says Billick, "he was in perfect position to make the throw."

Bradshaw often threw off his back foot, with a pronounced wrist snap. The Eagles' Michael Vick also throws conspicuously with his wrist. "More wrist in his throw than anybody I've ever seen," says Schaub, who backed up Vick for three seasons in Atlanta. "But nobody has given him enough credit. When he set his feet, he rarely threw a nonspiral, and he could throw the ball as hard or as far as anybody you could ever find."

The shotgun formation, ubiquitous at the college level and common in the NFL, has altered throwing dynamics. "It's made people sloppy," says Clarkson. "When you're in the shotgun, you're not forced to bring everything together, the way you do in a five-step drop from under center. Tim Tebow, who I think is a heck of a football player, clearly had his development slowed by playing in the shotgun."

ARM STRENGTH

Big guns get the buzz. "After my senior year in college [at Indiana] I went to the combine in 1993," says Trent Green. "When you get invited to the combine, you're pretty confident. You feel good about yourself, and you just want to go there and prove it. Everybody is that way. Then Drew Bledsoe came out and his velocity was different, the spin on his ball was different, and it was like, O.K., now I see why he's the Number 1 pick."

There remains a significant mythology surrounding Jeff George, who came out of Illinois in 1990 regarded as one of the most powerful throwers the game had ever seen. (Like Bradshaw, he gripped the ball with his index finger near the point.) "I went to Jeff's workout at Illinois," Kennan recalls. "I think Jeff just got off the plane from spring break, changed out of his flip-flops and completed about 60 straight balls. Unbelievable velocity. And the ball was catchable, too."

Mariucci worked George out in Detroit—when George was 38 years old. "He could still throw it," says Mariucci. "Great arm." Yet George's teams won only 46 of the 124 games he started in the NFL.

Bert Jones, who played nine years for the Colts and one for the Rams from 1973 to '82, is also regarded as possessing one of the strongest arms in history. "Bert could get it wherever he needed to get it," says Archie Manning, who played in the same era as Jones. Bobby Douglass, a strapping, run-first, T formation quarterback at Kansas, played parts of 10 seasons in the NFL from 1969 to '78 and could split receivers' hands with his passes. But he also threw 64 interceptions and 36 touchdowns.

Among current QBs, Favre's arm strength is legendary; the Bears' Jay Cutler is the heir. But velocity alone isn't much more than a novelty. A pass thrown hard must also be thrown accurately and at the right time to the right receiver. This is why the big arm is just one piece of the passing jigsaw. Says Bratkowski, "Lots of guys without real strong arms could make every throw. That's the difference between a thrower and a passer."

On the practice field in Houston, Schaub mimics a drop-back and looks off into the distance. For every word spoken, written and broadcast about mechanics and arm strength, the completed pass returns to what Rivers called "a natural feel." Now Schaub is recalling a Week 2 completion to Andre Johnson on the tying drive in what became a 30--27 overtime victory against the Redskins. "So many throws at this level are what you call faith throws," says Schaub. "On that play I'm throwing the ball 18 yards between the numbers and hash marks, and when the ball comes into that window, Andre has just got to be there."

Scouts call passers who get the ball into open spaces before receivers arrive "anticipatory" throwers. That skill is fundamental to accuracy at the highest level. "If you ever watched Dan Marino on end zone tape, he just had amazing anticipation," says Young. "He [wasn't mobile], so the ball had to come out. You could watch the view from behind and you'd think, Where is that going? He was throwing into nothing. Then, boom—a guy arrives.

"Joe [Montana] had that ability," Young continues. "Every football he threw had a message: Go there. There was no just throwing it and wishing it good luck. The really gifted guys send balls to a specific area. And of all the guys playing now, the guy who does that best is Tom Brady. The ball comes off his fingertips with a message. Guys are catching it running, and the whole offense is moving. He makes the most of every throw."

A quarterback or a coach will tell you that the ultimate measure of a pass is not its meaning or its appearance, but simply whether it's completed. And that's fair. But the ultimate measure of the passer is much more elusive.

"EVERY THROW HAD A PURPOSE," FOUTS SAYS OF PLAYING CATCH WITH A 40-YEAR-OLD UNITAS. "NOT NECESSARILY HEAT, BUT INTENSITY."

"ACCURACY CAN'T BE TAUGHT," SAYS YOUNG. "A LOT OF GUYS CAN SEE WHAT KIND OF THROW THEY HAVE TO MAKE, BUT THEY CAN'T MAKE IT."

"LIKE A BALLERINA," HOLMGREN SAYS OF MONTANA'S FAMOUS DROP AND HITCH. "THE WAY HE MOVED BACKWARD WAS SO SMOOTH."

FOR EVERY WORD WRITTEN ABOUT MECHANICS AND ARM STRENGTH, THE PASS RETURNS TO WHAT RIVERS CALLS "A NATURAL FEEL."

PHOTOPhotograph by WALTER IOOSS JR.JOHNNY ON THE SPOT Unitas, the quintessential quarterback, was famed for his distinctive over-the-top delivery. PHOTOTHOMAS CAMPBELL/US PRESSWIRECOLT OF PERSONALITY Manning, like Unitas, has a high release—and his football intellect overcomes sometimes awkward mechanics. PHOTOJOHN BIEVER (SCHAUB)TIP-TOP Like Steelers great Bradshaw (12), the Texans' Schaub extends his index finger nearly to the point of the ball. PHOTOHEINZ KLUETMEIER (BRADSHAW)[See caption above] PHOTORONALD C. MODRA (MONTANA)POCKET PERFECT Of today's passers, Rodgers (12) most closely recalls the tight, compact drop-back of Montana. PHOTOJEFFREY PHELPS/AP (RODGERS)[See caption above] PHOTOWALTER IOOSS JR. (NAMATH)UNORTHODOXY Namath (12) famously held the ball low and gave it a telltale pat before release; Rivers is known for his unusual shoulder delivery. PHOTOJOHN W. MCDONOUGH (RIVERS)[See caption above] PHOTOJOHN BIEVER (ELWAY)BODYWORK Elway generated tremendous power through his legs and torso; Brady, in contrast, stands tall and straight as he makes the throw. PHOTOHARRY HOW/GETTY IMAGES (BRADY)[See caption above]
HOLE YARDS PAR R1 R2 R3 R4
OUT
HOLE YARDS PAR R1 R2 R3 R4
IN
Eagle (-2)
Birdie (-1)
Bogey (+1)
Double Bogey (+2)