It is simple physics, a football Newtonian law of sorts. Yes, when the floodgates opened in the passing game and touchdowns were scored at a record pace this past season, it was the result of a remember-when generation of quarterbacks named Manning, Brady and Brees.
Yes, it was the result of a rulebook tipped by the league's decision-makers decidedly toward offensive players. It was the result of innovative, aggressive coaches who ditched the huddle and pushed the pedal to the floor at every turn.
But there is something else at work, something more basic, something rooted in force, mass and acceleration.
"This league is a bigger, faster, stronger league," Denver Broncos coach John Fox said. "And you win when you win matchups, and if you're the bigger, faster and stronger guy, you're going to win more matchups. That's not rocket science there. That's just the way it is."
In the explosion of record passing numbers, 5,000-yard seasons and the 55 touchdown passes by Peyton Manning that fueled the Broncos' record 606 points in 2013, the difference between offense and defense can be measured with a stopwatch and a ruler.
Now, not only are the wide receivers consistently getting bigger than the cornerbacks being asked to cover them, the data from this year's NFL scouting combine shows those receivers are getting faster, too. Twenty wide receivers were timed at 4.49 seconds or faster on the electronic clock -- the "official" time for the players -- in the 40-yard dash at this year's event.
Among the "smaller" group of cornerbacks, just 12 were clocked at 4.49 or better. So, in a bigger, faster, stronger league, there will be times when most of the cornerbacks in this draft class will be 0-for-3 against the players across from them.
"If you can find the size and the speed, you're always going to take the bigger player in any matchup," said St. Louis Rams coach Jeff Fisher, a former NFL defensive back, secondary coach and defensive coordinator. "But in my opinion, the gap between the height-weight-speed characteristics of the receivers and the DBs is widening, so there is even more of a premium on the taller, longer corner. But when you start looking at it, in terms of finding these players, there are more, a lot more, bigger receivers than bigger corners."
Numbers don't lie
In 1992, the wide receivers selected for the Pro Bowl averaged 6 feet, ½ inch and weighed 195.6 pounds. The cornerbacks selected to that Pro Bowl averaged 6-¼ and weighed 189.5 pounds. That's an even battle, much like it had been in 1982. By 2002, the gap had widened to 6-1¼ and 204.1 pounds for the Pro Bowl receivers compared to 5-11¾ and 194.3 pounds for corners.
By 2012, the Pro Bowl receivers checked in at 6-1½, 209.1 pounds and the cornerbacks averaged 6-¾, 198.4 pounds. The discrepancy grew this past season, with the Pro Bowl receivers averaging 6-2½, 215.8 and the corners going 5-11½, 196.4 -- even with Seattle's 6-3, 195-pound Richard Sherman and Arizona's 6-1, 219-pound Patrick Peterson in the mix.
Spin ahead to this past February's scouting combine, and a deep class of strikingly big wide receivers checked in at an average of 6-foot-1½, 200.1 pounds, while the cornerbacks invited to Lucas Oil Stadium averaged just more than 5-foot-11, 194.4 pounds.
Those are averages and include smaller speed receivers such as Oregon State's Brandin Cooks and Pittsburg State's John Brown, both under 5-foot-10, but the other receivers at the top of the board -- including Sammy Watkins (6-foot-¾, 211), Mike Evans (6-foot-4¾, 231) and Kelvin Benjamin (6-foot-5, 240) -- are physically bigger than virtually all of the cornerbacks at the combine. In all, 26 of the 48 wide receivers invited to this year's combine were at least 6 feet tall, while there were only nine cornerbacks who reached that mark.
Figure in those speed numbers from this year's combine, and the future headaches for defensive coordinators may only be getting bigger.
"It helps ... of course it helps, just look at it," Evans said. "I'm bigger and I think I'm faster. That's an advantage for me."
"That's going to be a real issue," said Dave Logan, a former wide receiver for the Cleveland Browns and Broncos who has won six Class 5A state titles as a high school coach in Colorado since his playing career ended after the 1984 season. "That's why there is such a premium on some guys with some size to them. Those guys have a chance to compete in the current environment."
Times have changed
When Logan played, he was an outlier at the receiver position. He measured 6-foot-5, and at the weekly Thursday weigh-ins during his career, he checked in anywhere from 227 to 232 pounds.
As one of just three people believed to have been drafted professionally in three sports -- he was selected by the Browns, the NBA's Kansas City Kings and Major League Baseball's Cincinnati Reds -- Logan was big and fast, with the coveted catch radius scouts like in a receiver, to go with an overall athleticism befitting his ability as a multitasker.
"But to look at me, I'm not sure they knew what the hell to do with me then," Logan said. "Is he a wide receiver? A tight end? They moved me to quarterback my second year in Cleveland and I was set to play there until [Paul] Warfield pulled a hamstring right before the opener. They moved me back outside and that's where I kind of stayed. Sam [Rutigliano, Cleveland's head coach] eventually asked me where I preferred to play, I said outside, and then they drafted Ozzie [Newsome] to play on the inside at tight end, and needless to say I stayed outside at receiver. But now it wouldn't even be a question, I'd be a receiver. I was 6-5 and ran 4.54 before my draft -- nobody would even hesitate now."
Logan's perspective as a high school coach -- and one who runs a complicated, wide-open attack on offense at that -- gives him the grass-roots view on what's happened. And he sees the end result on Thursdays, Sundays and Mondays, as well as from his vantage point as the radio voice of the Broncos on game days.
"If you're an athlete and you have skills with the football, their first idea is to put that guy on offense," Logan said. "Absolutely true. Sure, now, you've got to have some guys on defense, but if you see the athleticism, superior athletes, with skills with the ball, they're going to be receivers.
"The guys like Champ [Bailey] that have just that innate ball-catching ability are pretty rare. I'm not sure you see too many of those guys anymore on defense," Logan continued. "Champ, and I've watched him catch the ball many times for a long time, he has wide-receiver skills catching the football; most defensive backs do not. I think there's a better-than-average chance, a big chance really ... because of his ability to catch the ball, he would have been a receiver in the current environment."
Bailey did play on both sides of the ball during his career at the University of Georgia -- he finished with 59 catches and 21 rushing attempts -- but when the NFL came calling, scouts saw the flexibility in his hips, the top-end speed and the elite change-of-direction skills to go with rare ball skills and saw a potential Hall of Famer at cornerback.
And while Bailey routinely lobbied his coaches to try him out on offense -- former Broncos coach Mike Shanahan dabbled with the idea in training camp from time to time -- his value was greatest on defense, and that's where he stayed. Earlier this year, Bailey, who recently signed with the New Orleans Saints after 10 seasons in Denver, said he thinks he'd have been given a far longer look on offense had he entered the league over the past three or four years.
"I think there is just a different philosophy with it all than even when I came in," said Bailey, who was drafted by the Washington Redskins in 1999. "But when they really clamped down on the DBs with the contact, it was a lot more difficult to combat the size advantage. Now you have to do it with anticipation and positioning. You can't lock on and do some things down the field. Once the bigger guy has the position, that's it, and if he has the speed advantage or it's even, that's it, too. Put all that together and you're going to funnel those guys to offense because they can impact how many touchdowns you score."
Slanted toward offense
The league's recent rule changes to promote player safety also can be seen as a disadvantage for defenders.
"And the last few years the league has really moved to protect the receivers in the middle of the field, too," Logan said. "It doesn't pay a defense to have the biggest, baddest guy in middle of the field. They play a different brand of football and I think in many ways the defenses are still adjusting to all of this when you have those athletes out wide."
It all means the hunt is on for bigger cornerbacks, to find those big, tall, fast defensive backs who have escaped the constant pursuit of offense as they have progressed toward the NFL. It's why many personnel executives around the league are routinely moving bigger cornerbacks up their boards during the draft and selecting them earlier than expected.
The Seahawks, who finished first in the league in total defense, scoring defense and interceptions this past season, only put the exclamation point on it all when they buried the record-setting Broncos in Super Bowl XLVIII for a championship won resoundingly by defense.
The Seahawks made the move to bigger players in the secondary, often selecting them in the middle or late rounds or even getting them as undrafted free agents. Sherman, a first-team All-Pro in two of his three NFL seasons, ran a 4.54 40-yard dash at the scouting combine in 2011, not speed that would have earned him a double-take from scouts.
But what he does have are instincts to the ball and a big reach.
"You need that length, that wingspan to play bump and run," said ESPN analyst Herm Edwards, who like Fisher has a résumé that includes NFL defensive back, secondary coach, defensive play-caller and head coach. "And the bottom line, in the end, is how the guy plays the ball. When the ball is going downfield, the guy who can still play the ball with his back to the quarterback, when you've got a guy like that you've got a special guy -- a guy with the ability to play the ball even if they don't see it come out of a quarterback's hand. The good ones, the really good ones, have that innate ability to find that ball at the right time."
Take those qualities to go with the size discrepancy, and the talent pool at cornerback grows even smaller. Even Seattle coach Pete Carroll, who has been repeatedly asked if others in the league will now imitate the Seahawks' plan, sees a limit for those hoping for some kind of a copycat performance.
"Because they don't exist," Carroll said. "Big, fast guys are the fewest people around. Everybody would like to get longer, taller guys that run 4.4. But there are just not very many humans like that in the world, you know. So it's rare when you find them and then you have to develop the guys. The perfect guys are not there because there are not tall, exceedingly fast guys. Other than Calvin [Johnson], there are a handful. So you have to make those guys come to life in your coaching and how you adapt your style and your ability to fit it."
"This is nothing new -- this goes back 20 years -- but it's just rare that you can find them," Carroll continued. "When we had Brandon [Browner] and Richard [Sherman] playing, you can't get any longer. Those are the two tallest cornerbacks to play together arguably in the history of the league. So it's, 'Well, let's go do that.' But there are no players like that. Look at this draft -- there are only a couple of guys over 6-1 at corner."
At this year's combine, there were only six.
Cyclical nature of things
As a result, Fisher, Edwards and others in the league believe there will be increasing focus on how receivers are defended in the 5-yard chuck zone. To disrupt the timing of plays, defenses can try to force the receiver to deal with at least some contact before he gets up to speed.
"Guys lining up on them right on the line of scrimmage, I think that's coming back in our league," Edwards said. "You look at how successful Seattle was with physical guys who might not run as fast as some others. If you can win at the line of scrimmage, not let them get to their top-end [speed], those first two yards are going to get more important. And those things at the line of scrimmage, you can teach that, that's fundamentals, easier to teach than those innate ball skills in space."
And in the end, many in the league are quick to acknowledge what is happening and offer reasons why, but they are just as quick to point to the cyclical nature of things in the NFL, as the actions draw reactions that force new and different actions to spin the wheel again.
Also, Logan said, the current crop of top-end pocket passers, even for the accolades that are continually showered upon them, still might be underappreciated for their roles in all of this.
"It'll swing back, I don't know when. I'll be interested to see what the landscape looks like when Peyton, [Tom] Brady and [Drew] Brees, those pocket passers, are gone," Logan said. "Because the next wave of quarterbacks, other than Andrew Luck, I'm not sure the next wave of quarterbacks will be turned loose to throw it 50, 55 times a game because of the schemes they play and the types of quarterbacks they have. So, at least some part of it may be these once-in-a-lifetime quarterbacks, too."
"It's just where we find ourselves," Fisher said. "The shutdown corner, the guy who can play down the field and is strong enough to play at the line of scrimmage with the ball skills to match the receivers he's covering, is harder to find than the big-play receiver. And that's if they're the same size. Add in those height-weight discrepancies, and you have the problem we all face right now on defense. It's harder to win a matchup you have to consistently win to succeed on defense."