Get ready, 'cause here it comes.

Bleacher Report colleague Ty Schalter and I have spent a good deal of time this season talking about the evolution of the NFL game. From how it turned into a quarterback league—and is staying that way—to the death of offensive lines and running backs as we once knew them.

Ty broke down what makes today's offenses so explosive, and he even told defenses what to do to slow them down. Meanwhile, I set up the blueprint for stopping the latest breed of NFL passers. 

What if I told you that there was an offensive system on the horizon that could switch things up even more? What if I told you that the next stage in NFL evolution could dramatically increase scoring and completely change the way NFL teams are run?

Meet the Air Raid offense—one part West Coast passing philosophy, one part Chip Kelly-style uptempo attack, one part screen-passing attack with some dashes of whatever else a particular coach thinks is important.

It's taken over the college game, and it's coming for the NFL next. 

A Brief History of the Air Raid

The most famous coach who employs the Air Raid is also one of its innovators: Mike Leach, now of Washington State. He, along with current Southern Methodist offensive coordinator Hal Mumme, helped create the now-infamous passing attack. The two coached together first at Iowa Wesleyan and then eventually at Kentucky. 

Bah, it's just a gimmick! 

As Leach eventually broke with Mumme and headed to Oklahoma as offensive coordinator and then Texas Tech as head coach, he was reviled, ridiculed and soundly rejected by established football minds who wrote him and his system off as too contrarian to work in "real" football. 

Leach left Texas Tech following a well-publicized feud with then-ESPN personality Craig James and his son, Adam, who was a receiver for Leach at the time. He resurfaced at Washington State, where he has yet to truly turn the program around. 

Mumme, for his part, has mostly languished since Kentucky. Now 61, his biggest success post-Leach has been resurrecting Southeastern Louisiana University's football team and getting McMurry University to a Division III playoff win. 

A funny thing happened to college football, however.

While it might be logically sound to conclude that Leach and Mumme have struggled because college defenses "figured out" the Air Raid, the opposite is true. Rather, college offenses have incorporated Air Raid principles almost across the board. Take a look at any college team, and it's likely that they've installed something—even if it's just a small portion—right out of that old Kentucky playbook. 

Moreover, the Air Raid has collected even more staunch defenders (offenders?). Some of the most prolific college offenses utilize the system. It's been tweaked by some of the game's best offensive minds, including Baylor's Art Briles, Texas A&M's Kevin Sumlin, West Virginia's Dana Holgorsen, California's Sonny Dykes, Texas Tech's Kliff Kingsbury, Oklahoma's Josh Heupel and many other coaches at smaller schools. 

Oh, and don't be mistaken, it's been adopted to some extent by a lot of NFL teams as well. That is no surprise since that's where the ideas came from in the first place.

The Air Raid Permeates Through the NFL and Has For a Long Time

When you think Air Raid, think Sid Gillman. 

Gillman, the legendary former Chargers coach, didn't run the Air Raid, but he pioneered many of the concepts that exist in it. Of course, he pioneered many concepts that exist in any system that include the forward pass, but that's kind of the point. 

While the Air Raid is looked down upon as a college offense, it was once a stark departure from the run-heavy sets that dominated the collegiate landscape. It is, just as prominently, a descendant of Gillman's attack. It counts among its brethren: the West Coast offense, the spread and Don Coryell's vertical passing attack.

For years, however, the Air Raid has been the black sheep in the family as far as the NFL is concerned, even though the other siblings have been cribbing notes.

LaVell Edwards was a known piece of source material for Mumme and Leach as they put together their offense. Edwards coached at Brigham Young for decades as both an assistant and head coach. His coaching tree includes NFL men like former Green Bay Packers and Seattle Seahawks head coach Mike Holmgren, former Oakland Raiders offensive coordinator Ted Tollner, former Baltimore Ravens head coach Brian Billick, Kansas City Chiefs head coach Andy Reid and more. 

Because of Edwards' intricate connection to the NFL and the Air Raid's close relationship to the West Coast passing attack that many of his proteges helped evolve, it's no surprise that NFL teams have been well indoctrinated in the concepts that Leach, Mumme and others have been preaching. 

Another source of some of the Air Raid's core concepts is Mike Shanahan, who introduced the shallow cross series (h/t Chris Brown of Smart Football). Yet the teacher has become the pupil; Shanahan was forced to implement many of Briles' Baylor schemes into his Washington offense with former Baylor quarterback Robert Griffin III at the helm.

As an aside, I mentioned Chris Brown above, and if you're interested in the Air Raid (or X's and O's in general), he's the go-to source. I've learned a lot from reading him at Smart Football, Grantland and in his published work over the years. 

With former Shanahan disciple Gary Kubiak in charge, the Houston Texans have also thrown some more Air Raid into their offense with former Houston quarterback Case Keenum taking the snaps. 

Marty Mornhinweg, another West Coast aficionado, has done much the same after former Air Raider Geno Smith took over for noted buttfumbler Mark Sanchez. 

If you're sensing a theme or two, you should be. First, the West Coast offense, which in its infancy helped develop many of the ideas in the Air Raid, is a pretty easy melding point for the Air Raid in the pros. Also, the more college quarterbacks well-versed in the system are pushed to the forefront, the more important the system is going to be to the NFL landscape.

If you're thinking that you were born two decades too early, you might be former Kentucky quarterback/NFL draft bust Tim Couch.

Looking toward the draft horizon, quarterbacks like Texas A&M's Johnny Manziel, Baylor's Bryce Petty and Eastern Illinois' Jimmy Garoppolo could all be Air Raid quarterbacks taken. When you add in spread quarterbacks like Clemson's Tajh Boyd, Fresno State's Derek Carr, Oregon's Marcus Mariota and others, the crop of quarterbacks is looking a lot different from what used to be considered "pro-style."

It isn't just quarterbacks, either. Offensive linemen, receivers and backs in those schemes all have little wrinkles to their game that are slowly making their way up into the NFL ranks. It's also making it more difficult for teams to ignore the offenses that produced those players.

Consider how New England Patriots coach Bill Belichick used Wes Welker. Although they already utilized more of a spread look, the addition of Welker gave them the ability to run all sorts of screens and crossing option routes straight out of his old Texas Tech playbook.

It doesn't mean that the Patriots were running the Air Raid, but it certainly means that they took parts from that system and installed them in their own. It's the same thing teams have done around the league with players like the aforementioned quarterbacks, wide receivers like the Patriots' Danny Amendola and others.

That trend isn't changing anytime soon.

It isn't just the players, either. Briles was quickly becoming a hot name in NFL coaching circles until he signed a 10-year extension to stay at Baylor. Sumlin might be the hottest college-to-the-NFL name after losses have taken some of the luster off Notre Dame's Brian Kelly. 

The Air Raid is coming to the NFL. The only question is when. 

OK, So What Is the Air Raid Anyway? Oh, and How Can NFL Defenses Stop It?

We've established that the Air Raid has already sunk its teeth into the NFL and that it's here to stay, so what does it look like? How do you know when you're seeing it? What differentiates this from the normal spread offense?

A super simplistic way of looking at it (and thus not entirely accurate, but it's good shorthand) is that vertical passing concepts are the portion of Sid Gillman's old scheme that Don Coryell, and others, have used to create what we would call a vertical passing attack. That leaves the horizontal passing concepts for the West Coast scheme and the Air Raid. 

Again, it's not a perfect way of talking about it, but it gets us part of the way there. 

One of the core route concepts in the Air Raid is the shallow cross and its brother, the mesh route. In the shallow cross, the receiver (often an inside receiver) cuts immediately toward the middle of the field, right behind the defensive linemen. He catches the ball a yard or two past the line of scrimmage and is tasked with getting yards after the catch. 

In the West Coast passing attack, the slant does roughly the same thing, but it is more of a timing route at three to five yards out rather than a crossing route which takes advantage of freeing oneself in the middle-of-the-field traffic. 

The mesh route helps create that traffic by running two shallow crosses at one another. You'll hear commentators refer to this as a "pick play" or a "rub route."

Again, this is speaking in absolutes, and offensive philosophy doesn't really work like this, but a "rub route" or running into traffic is the antithesis of the purest forms of the West Coast attack. The West Coast sets up routes to draw traffic away from receivers. The Air Raid creates the havoc and then benefits from it. 

Of course, if we're talking about traffic, we need to mention screen plays, which the Air Raid utilizes to their fullness. The wide receiver screen, bubble screen or middle screen are Air Raid staples. Even the shovel pass—a companion to the screen and the draw—finds its home in the Air Raid. 

The final core pass play to cover here is the Four Verticals (there are more core plays, certainly, but this one gets the most play in the NFL). "Wait!" I can hear you saying. "But you said that the Air Raid was more about horizontal pass plays!"

In Four Verticals, the idea is not to stretch the field vertically and take advantage of the space underneath. No, the four vertical routes still stretch the defense out horizontally across the field and create wide-open seams in which to throw. Yes, it's a vertical pass play, but it's still stretching a team horizontally.

Yes, New Orleans Saints, Detroit Lions and Chicago Bears fans (among others), your team has the Air Raid to thank for that gem of a play.

Moreover, top receivers like Calvin Johnson and Brandon Marshall have the Air Raid to thank for the back-shoulder throw. That's a Leach staple too.

It makes sense—push a defender down the field and then have the option to beat him over the top or simply stop and let him keep running as you catch the ball. 

It was also born a bit out of necessity, as elite speed and arm strength have usually been at a premium in Air Raid schemes. Giving backs and receivers the ability to cut off routes rather than consistently throw over the top just worked better when the quarterbacks and receivers were smart and well-versed in the scheme but not elite natural athletes. 

From a defensive standpoint, the way you cover these concepts is with smart zone coverage.

If everyone passes receivers off to their teammates without running into one another, the crosses and mesh routes don't work as well. If the deep safeties keep the play in front of them without getting turned around, the Four Verticals don't work as well either. 

That means everyone has to cover—corners, safeties, linebackers, everybody. You have to win at the line of scrimmage as well, because there are simply too many receivers out there running routes, and the quarterbacks are taught to find the open one. Even if coverage is perfect for a second or two, no coverage stays perfect any longer than that. 

The Air Raid's continued and increasing assault on the NFL will also pressure defenses to tackle better. The common derisive knock against "college" offenses is that they won't work against the better athletes in the NFL. However, while that's true, fundamental tackling isn't exactly great in the NFL these days, especially as defenders struggle to adapt to the new contact rules. 

Even more than tackling, the defensive backs need to be ready to be physical against Air Raid looks. Taking on blocking receivers sounds like it should be a cakewalk, but not when you're supposed to take off and backpedal at the snap and the receiver is a couple of inches taller and 20 pounds heavier. 

From a schematic perspective, teams need to favor zone coverages to man in order to avoid increasing the traffic-clogging nature of the scheme. A lot of inventive defensive coaches also end up using hybrid-style fronts with only two or three down linemen in order to confuse the quarterback and give him looks he's not used to. 

All that said, defenses still struggle to stop the Air Raid because it is built to put up a ton of points. If run to perfection, there's no real solution for it; a talented play-caller can still find a weakness somewhere in a defense.

For that reason, more than any other, teams are going to continue to implement changes to their offense in line with Air Raid principles, and it's only a matter of time until someone brings in the scheme wholesale.

We've asked if the NFL is ready. Perhaps a better question is: Are you?

Michael Schottey is an NFL National Lead Writer for Bleacher Report and a member of the Pro Football Writers of America. Find more of his stuff at The Go Route and follow him on Twitter.