I mentioned to Falcons coach Dan Quinn something I heard a lot this summer during my tour of NFL training camps. “When looking at tape now, you can’t just look backward because …”

Quinn finished my sentence for me.

“You have to look forward,” he said.

What he means, of course, is that the NFL currently moves at a quicker pace than at any point in its history: A trend can appear more quickly and evolve faster than ever before. Schemes were essentially a closed loop in the last few decades of football. Now coaches have to project which offensive schemes from any level of football might make their way to the NFL, much like the RPO did three years ago. Advances in technology and smarter, younger coaches mean that schemes develop and travel at warp speed. If these were the only problems NFL defenses faced, it would be enough. Instead, they are just the newest ones.

I’ve spent the past couple of months asking the NFL’s top defensive minds a question: Can NFL defenses ever stop offenses from setting leaguewide records every season? The short answer, I found, is no. The longer answer is that there are some ways to introduce new schemes and develop more flexible athletes, but that answer also ends in a no.

Sometimes cyclones combine to make bigger ones—it’s called the Fujiwhara effect—and this is what happened to defenses this decade. Essentially, every movement over the past decade went squarely against NFL defenses. Even the most stubborn coaches, after years of resistance, finally began utilizing the spread en masse in the past two years, stretching defenses out farther than ever. They joined coaches like Andy Reid and Josh McDaniels, who have been implementing it for most of the decade. A handful of other factors have contributed to this offensive evolution: quarterback development at the youth level is better than ever; there’s an absurdly talented generation of wide receivers; and there has been a slew of rule changes, ranging from a crackdown on illegal contact to stricter penalties on quarterback hits. All of these trends have favored offenses. Patrick Mahomes exists. Tom Brady will play forever. These players would inflict pain on defenses in any generation, but when they get every break, well, you can forgive defenses for giving up 40 points a lot. It helps ratings and makes for a more exciting product. The rule changes are designed to make the game safer. But half of the league—as in every defender and every defensive coach—is left trying to figure out what to do.

Defenses can claim some individual successes. The Patriots look like they might have their best defense in years this season. Seven months ago, they held the Rams, the era’s offensive darlings, to three points in the Super Bowl. It helps to have the best coach in the history of the sport, of course, but the Bears, Bills, and Packers also look to have strong defenses in 2019.

The story of defensive performance in the NFL as a whole, however, is quite ugly: Last season, three teams averaged more than 30 points per game, tying a league record. Through the first month of this season, five teams are hitting that mark. Last season, eight quarterbacks had a rating above 100, which is two more than had managed that feat in any season in history. At present, there are 11 starters currently hitting that mark this season, and that does not include elite passers like Tom Brady and Deshaun Watson, who are both hovering slightly below 100 and are likely to get there at some point. The NFL set a record for completion percentage in 2018—a number that’s being equaled so far this year.

“It’s now fast-break football and unfortunately, we are capitulating to it because of the rules,” Panthers coach Ron Rivera said.

Complaining that you can’t play defense is as old as football itself. Paul Zimmerman’s 1984 classic The New Thinking Man’s Guide to Pro Football is full of defensive players and coaches griping about how the league doesn’t want defense. This is different. Statistically, this is the horse getting out of the barn, and the horse scoring 35 points on the Bengals.

The coaches and executives I spoke with realize that it’s misguided, at best, to compare current defenses with those from past eras. The sport has changed too much in a short time. In Buffalo, scouts are instructed to emphasize cornerbacks who can tackle because completion percentages are so high that limiting yards after the near-inevitable catch has become essential.

“It’s becoming a seven-on-seven league,” Bills general manager Brandon Beane told me, referencing the type of youth football game played with only passing plays. “Cornerback play is vital. A lot of it just used to be on the front [seven]. But if your front is dynamic and wreaking havoc, coordinators are having guys get the ball out quick. So it’s important that cornerbacks have to be able to tackle, that linebackers can get out there.”

The phenomenon Beane describes is another part of the sport’s offensive evolution that defenses have to contend with: Teams have gotten extraordinarily good at getting the ball out quickly to neutralize the pass rush. You can still have plenty of success with Khalil Mack rushing the quarterback, but offenses have gotten pretty good at game-planning away pressure. (The Bears threw the ball in an average of 1.5 seconds every time Aaron Donald was single-teamed in a Rams-Bears game last year, according to Pro Football Focus.) A completion is taken as a given as teams focus on shorter, quicker passes. “I think what you’re trying not to do is have the pass not beat you over the top. If you keep it in front of you, play downhill, that’s great. The rules now are so much in favor of creating those types of opportunities,” Rivera said.

When you talk to people in the league about defenses, most of them focus on what happened to the middle of the field. Sports Illustrated once called a bad pass over the middle in front of Eagles star Chuck Bednarik “life threatening,” which is only a mild understatement given what Bednarik did to opponents over the middle, particularly Frank Gifford. This was true in the 1960s; it was true, Rivera tells me, when he played; and it was true when Antoine Bethea, the Giants’ 35-year-old safety, entered the league in 2006. “That’s what you wanted. So that you could set the tone,” Bethea said of the previous era of big hits. “Now receivers don’t have that caution.”

Bethea is unsure whether there is anything defenses can do to regain the ground they lost to offenses. “The way the game is being called, what defensive players are allowed to do and what they aren’t allowed to do, and then the type of players on offense—receivers and tight ends who are bigger, stronger, and faster,” Bethea said. “I couldn’t even give you an answer. As a defensive player, the changing rules—can’t touch them, can’t hit them. We’re behind the eight ball.”

The rule changes Bethea is referring to, which protect defenseless receivers, were necessary for safety. Players getting plowed in the middle of the field, with a defensive back and receiver both running at full speed, is the type of collision the NFL wants to eliminate from the sport. Laudably, egregious hits are followed by flags or ejections. The side effect is that entire offenses are now built around exploiting the freedom of movement that is available in the middle of the field as a result of those changes. The emergence of the modern slot receiver came in 2007, when the Patriots used Wes Welker to perfection. (They were also the first team to run a majority shotgun offense, which is now a staple of nearly all NFL offenses.)

Over a decade later, using the middle of the field is a default method of operation: Rams quarterback Jared Goff threw a remarkable 80 percent of his passes to the slot last season. Football Outsiders, which tracks throws to wide receivers in the slot, has the number increasing leaguewide for all three years on record, with 2018 clocking in at 55 percent. Though numbers are not tracked for all of NFL history, there has never been an era quite like this in modern football.

“Quarterbacks stopped throwing over the middle because receivers wouldn’t go over the middle. Everything was really underneath or on the outside,” Rivera said of his playing days. “The way the rules are, it’s nothing to see a guy run a deep 18-yard dig [route]. Back in the day you’d see that and say, ‘A safety is going to take that guy’s head off. Literally.’ And now there’s some quote-unquote entitlement [from receivers going over the middle of the field].

“As a fan, you see those guys make some of those catches, that’s exciting. We’ve got guys who do that. As a defensive guy, I’d like to see those guys get hit.”

There are many remarkable aspects of the New England Patriots’ two-decade run, but one of the most impressive is their ability to hang in any type of game. A year after losing to the Eagles 41-33 in the second-highest-scoring Super Bowl of all time (Oklahoma coach Lincoln Riley told me it looked like a Big 12 game), the Patriots played in the lowest-scoring Super Bowl of all time, and won, in a 13-3 defensive struggle against the Rams. It is easy to say that in doing so, the Patriots established a blueprint to stop the Rams, but this is simplistic. Replicating the Patriots, as 20 NFL seasons have shown us, is hard to do. You’ll need Bill Belichick to do it well. The Rams have been slowed slightly, and Goff looks worse this season than last, but they are still sixth in the NFL in yards per game and seventh in points. Goff just threw for 517 yards in a loss against a good Tampa Bay defense.

The Patriots (along with the Vic Fangio–coached Bears) did implement a tactic that helped contain the Rams last season; it’s the soft 6-1 defensive front the Bears used on the Rams offense last season, and one the Patriots tweaked to near perfection. The Saints and Browns have also used it this season. However, we’ll need a larger sample size before we bury the Rams.

It should not be much of a surprise that Belichick found a way to hold the Rams to a field goal. This is what he does—he builds game plans that home in on what a team does best and wrecks it. In the Super Bowl, that involved moving cornerback Jonathan Jones, who contained Chiefs wide receiver Tyreek Hill in the AFC title game as a corner, to safety. Jones led the team with eight tackles and recorded a sack.

“They took the fastest kid they had on their roster, and they put him at safety, and then they took the safety and rolled him down and put him outside the tight end so that they had speed to the outside in case anything were to bounce [outside],” said Cody Alexander, a high school coach in Texas who runs MatchQuarters, a website devoted to defense. “They really only had two defensive calls, it was crazy.” Jones’s speed at safety, Alexander explains, meant that the Rams could never outrun him on crossing routes. “I think the future is really trying to find more of these hybrid type of defensive backs,” he said. “What the Patriots did was simple. I don’t think people understood how simple it was, and then they got multiple blitzes on third down.”

TCU’s Gary Patterson is a defensive-minded coach in the pass-happy Big 12 who’s chatted with NFL coaches about stopping college-style offenses. Patterson told Sports Illustrated that Belichick’s genius was running those two defensive calls and waiting to see what the Rams would do at the line before committing to either one.

This type of adaptability—the defensive version of what the Rams offense is widely praised for—is crucial to the future of defense. Quinn explains that “there’s so much that takes place at the line with offenses that defenses have to be adaptable.” Defenses, Quinn thinks, must have the same amount of flexibility. ”It’s not just a run/pass check at the line anymore for offenses,” Quinn said. “It’s not your best call vs. their best call anymore. The best team defenses can have versatility, too. It should be, ‘OK, you want to check into these looks? We just did too.’ I’m not saying you can morph into an offense, but you have to have the ability to do the same thing back to them.”

He continues: “That means more guys on their feet [instead of three-point stances], more speed than ever. The offenses are featuring more three- and four-receiver sets so the defenses are featuring more nickel, more fast linebackers.”

Nearly everyone I spoke with agrees that the solution to achieving this adaptability is having more flexible and athletic defenders. But these players are unique, and not every team has the best defensive coach of all time. It would be helpful for a team to have 11 players who can play every position, à la Dutch soccer’s “Total Football” teams from the 1970s, but there are not a ton of heavy, tall, fast players who can keep up with anyone on the field. It is a supply problem, not a failure of imagination.

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The Patriots value positional flexibility, and their ability to briefly turn Jones into a safety rather than a cornerback with 4.3-second 40-yard-dash speed shouldn’t come as a shock. But the NFL needs more of this kind of thinking and these kinds of players. “I think,” said Giants safety Jabrill Peppers, a famously versatile player, “the future is more speed guys on the field—smaller, nimble linebackers, faster safeties, even more nimble D-linemen. You can’t really touch, hit anybody, and the way the game is going you have to cover a lot of ground.”

“I think what has filtered into the NFL is the college game,” Browns defensive coordinator Steve Wilks told me. “You have to have athletic players on the field. Look at Shaq Thompson, who can run with receivers.” Wilks, a former Carolina defensive coordinator, told me that this year in Cleveland, he sees safety Jermaine Whitehead having that sort of flexibility, and last year, as head coach of Arizona, he had safety Budda Baker.

Thompson was mentioned a handful of times by coaches inside and outside of the Panthers organization. He plays what Rivera calls “a Buffalo nickel.” “Shaq is put on a wide receiver, but he has the ability to fit into the box, he has the ability to cover,” Rivera said. “So now, offenses can do all they want. They’ve got Jimmy Grahams, or Greg Olsen, or [Zach] Ertz-type receiving tight ends. You have a guy who can compete against them and be physical with them. Or you’ve got these teams who have big wide receivers like Larry Fitzgerald who would come down and crush these nickels, now he’s got to battle a linebacker.”

The early results for 2019 are positive:

This might just be a "Shaq Thompson breakout season" thread. Dude is shoving around OL and handling one of the NFL's fastest RBs in coverage on a wheel route. pic.twitter.com/0lWt160Hgk — Will Brinson (@WillBrinson) October 1, 2019

Rivera said the Panthers decided to get more athletic on defense in the offseason because of the way offenses have evolved, and after watching the Patriots in the playoffs. “Watching what Bill Belichick did, I kept thinking to myself ‘God, you have to put as many athletes up front in your front four—or five or six or seven—to chase down these guys,’” Rivera said. The Panthers have learned the lesson and retooled their front seven by drafting Brian Burns and signing Gerald McCoy, among other changes. It is not a surprise that athletes are the future, but the NFL will need a lot of them on defense.

Quinn and Rivera both mentioned mobile quarterbacks and how important athletes are to stopping them. “The original guy was Thomas Davis. [Carolina] drafted him to chase Michael Vick,” Rivera said. “That’s what you have to do now. You can have great athletic corners and safeties, but if your quarterback can create time, those guys will get open. Those guys will, at some point, win, so you have to chase them.” Davis, who spent 13 years with the Panthers, left for San Diego this season. His replacement is the team’s former first-round pick: Shaq Thompson.

All of the coaches I talked with agreed that at the NFL level, trends now pop up from the high school and college game quicker than ever. This means the spread. It means the RPO, which helped the Eagles win the Super Bowl two years ago. It means Kliff Kingsbury’s offense in Arizona. It means that offenses evolve at a faster pace than ever.

“You have to look at the college game as a whole. We study the college game more than we ever have in the past because no. 1, you look at the quarterbacks coming out—Baker Mayfield, Lamar Jackson, Kyler Murray now. Coaches are putting those guys in positions where they are most comfortable, and that means bringing a lot of the college game to the NFL,” Wilks said. “So we study a lot of the college game in order to stay ahead and, most importantly, understand the adjustments when it happens.”

Alexander thinks that in the same way NFL offenses evolved by liberally borrowing from the college game, defenses will have to do the same. This would include the tite front, a college scheme that clogs up the middle of the field in an effort to force everything to the outside. The 4-0-4 tite front is now celebrated in major college football. The bear front, similar to this, is a tactic the Packers have used with success this season and one teams will likely have to implement leaguewide.

“The multiplicity and the diversity you see at the college level will have to eventually make its way into the NFL. Everyone has seen Cover 1, everyone has seen 3 Buzz, and you can get to where you are predictable, and these quarterbacks and offensive coordinators know that predictability. I’m amazed at how vanilla they are,” Alexander said. “You watch Alabama or Clemson, they are jumping in and out of things, creating havoc, and I know the NFL is a different game because everyone has the same toys to play with, but I think the multiplicity is something the NFL has to look at.”

So there are places the NFL can go to. But no one seriously thinks the numbers will ever return to what they were a decade ago. Passer ratings will never go down. Nearly all passing records will be held by current and future quarterbacks.

“Scoring points sells tickets,” Bills coach Sean McDermott told me. I tell him the rules aren’t changing back. “They aren’t. And I’m OK with that. Coming up as a defensive coach, I understand that. That’s part of the fascinating challenge of this league—to put in the time to understand where the trends are and are going. Trying to forecast where the trends are going while remaining fundamentally sound on defense.”

The fascinating challenge McDermott describes will not be ending soon. Or ever.