The NFL wide receiver's job is to get to a position where the quarterback can throw the ball without the defender interrupting the play. It's a basic game of "keep-away" with an incentive to move towards one end of the field. Naturally, this concept has developed over time to minimize the possible variance of outcomes during a play. Receivers run to a point where the QB expects them to be. This gives the offense an advantage over a defender covering the play. The offense will have multiple pass-catching options on-field at the same time so pre-determined routes make it easier for a QB to anticipate how a play is unfolding, make the right decision, and complete the pass. Backyard football where you simply run around and "get open" won't work in the NFL because of the minimal time the QB has before he gets hit by defensive linemen. It needs to be quick, it needs to be smart, and it needs to be organized. This is why routes are important.

Routes

Here we have the basic receiver route tree. This details the standard route options available to a receiver in any given offense. Each number on the tree represents a different route, though it is important to note that the graphic above depicts a receiver aligned to the QBs left of the formation. A receiver aligned on the right would use a mirror image of this tree. The easiest way to remember it is that the even numbers direct you towards the center of the field and the odd numbers go to the sideline.

[1] Flat

A quick route where a receiver bolts off the line, breaks at three steps, and powers toward the sideline.

[2] Slant

This is a common route for quick passes. The receiver uses either a one or three-step break towards the middle of the field diagonally. This is often run from a slot-position, but can just as successfully be run from the outside.

[3] Comeback

The receiver runs downfield past a standard first-down marker, often pressing directly towards the defender, then makes a sharp break (12-15 yards), and turns backward to the sideline. This route requires the QB to throw the ball before the receiver breaks at the top in order for the ball to be there when the receiver turns. Any hesitation will allow the defender to jump the route for a possible interception.

[4] Curl

This carries the same principles as the comeback route, except it's a much easier throw for the QB because the receiver puts himself between the QB and the defender. In order to make a play on the ball, the defender has to "go through" the receiver.

[5] Out

This route has the same break point as the others (just beyond the first down marker, or 12-15 yards), but requires a combination of efforts. The QB has to make the same precision pre-break throw as the comeback route, but the receiver - who is traveling directly towards the sideline - has to stay in bounds during the process of the catch.

[6] In

An in route is very different to the out route in terms of what you're trying to accomplish. Here, you're looking to get separation from the defender on the outside, but also enough depth to get behind the linebackers. The receiver needs to sell a deep or outward breaking route, cut inward, then the QB has to make a throw into a "window" between and/or over any front-seven players in coverage.

[7] Corner

You run to the corner. A lot of these are self-explanatory. The receiver begins with a deep drive, then breaks high and to the outside towards the sideline (or corner of end zone if in range). The aim is to divert the receiver away from any safety help in the middle of the field.

[8] Post

You run to the goal post. This route exposes any holes in center-field coverage. A single-high safety overcommitting to one side will be punished with a post route, as will any significant gaps in a two-deep defense.

[9] Go

How fast can you run? Okay, go! Straight-line speed and deep separation are a huge advantage for any receiver attempting a go route. In close-quarters scenarios such as red zone, this would be run as a fade route. If the receiver gets a clean pass on the defender, the QB will throw over the top. If the coverage is still tight, the back-shoulder throw is the target.

Advanced concepts

The basic route tree is just that; it's basic. It is the staple produce of an NFL playbook, but the simplicity of the tree means that it won't be enough to fool a top-class defense. In order to get open against guys who spend months studying game-tape, you need an arsenal of tricks.

Double move

Several routes operate under a double-move concept. It's not groundbreaking for a receiver's predetermined route to try and sell the defense with a fake before breaking into the desired direction. The sluggo (slant-and-go), out-and-up and the stop-and-go are all routes designed to fool a defense into biting one way, before hitting them with a second move in the opposite direction.

Option routes

If an offensive coordinator trusts his receivers, he can employ option routes into the playbook. These are a risky proposition as it gives the receiver multiple possibilities on a single play. The receiver reads the defensive alignment and then determines how to run his route based on how he thinks he'll be covered. The difficulty here comes from the requirement for the QB to read the defense the same way the receiver did. It doesn't matter who is right or wrong, as long as they are on the same page. If both players read it wrong, the QB doesn't have to throw it that way. If both players read it right, it should result in a good play. However, if a difference of opinion occurs, then the QB will likely be throwing to an area of the field devoid of offensive players.

Screens

A screen is a play designed to get the ball to a receiver with blockers out in front. One receiver turns to look for the ball shortly after the snap, while others around him block up defenders, creating a path for him to progress. This can be done from a stack formation with three receivers (one catcher and two blockers), from the slot (potentially to a tight end and using offensive linemen as blockers), or out of the backfield operating much like a running play. In any situation, the intended receiver doesn't progress much beyond the line of scrimmage and doesn't use much from the traditional route tree.

Ghost

Occasionally, a receiver will motion into the backfield either pre-snap or post-snap. This is called a ghost route, but is also known as a "reverse" or "end around." The QB can hand the ball to the receiver who now acts as a running back, throw it to the receiver while in the backfield, or allow progression with the receiver developing into an option from the standard route tree.

Splits

The receiver's distancing between the offensive line and the sideline is known as the split, and it's an important indicator for the defense when diagnosing a play. For example, a player using a "plus" split will be aligned wide outside the field numbers. This player will then be unlikely to try an out route (5) due to space restrictions. The defender will likely cover more towards the inside of the player and use the sideline to his advantage. Other options here include a numbers split (aligning to the field numbers, reduced split (an outside receiver aligning between the hash marks and the numbers), and the standard slot alignment. Each split presents a higher likelihood of certain routes to the defense.

RB route tree

A running back without the ability to catch passes is unlikely to be considered a starter in today's NFL. The idea of a "third-down back" is gone, and instead, we are presented with guys who land somewhere on the spectrum of running back to slot receiver. Players like Shane Vereen, Darren Sproles and Danny Woodhead offer as much on the ground as they do through the air, and their presence on their respective teams becomes invaluable when considering it from a defender's point of view.

Running backs, because they operate out of the backfield, require a modified route tree. Of course, I can't help but overstate the fact that these route trees will vary from team to team and offense to offense. What I have provided above is a section from Ernie Zampese's playbook from his time with the Dallas Cowboys. What the Cowboys use today will be different, and what Zampese may have used with another team may be different too. It entirely depends on what you require from that aspect of the game.

Route combinations

Now that you know what the routes are, you can learn about the various combinations used by offensive coordinators to draw defenders into compromising positions. The 'Summer School' series is about bridging the gap between basic knowledge and intermediate knowledge, so I don't go into a massive amount of detail or even cover all the options (that's a book in itself). The ideas outlined below are the core concepts needed to diagnose a play rather than put one together. If you're looking for expert-level analysis and a thoroughly enjoyable read, I recommend Matt Bowen's in-depth (and I mean like oceanic levels of depth) article about route combinations.

The knowledge of the receiver's projected path should give the offense an advantage in one-on-one situations. Route combinations aim to generate those one-on-one situations, because when you look at the math, the defense has a personnel advantage. Think of it this way, the offense dedicates a minimum of six players (five OL, one QB) to throw the ball into the stands, whereas the defense usually only rushes the passer with four or five players. The numbers favor the defense, so the offense develops patterns within the receiver routes to pull that advantage into undesirable areas. It doesn't matter if you're covered by one player or two, you're covered and you're out of the play. The basic principle of route combinations is getting those extra players to declare towards one specific receiver or area of the field, so that another features at best, one player to beat.

Hi-Lo

The Hi-Lo concept is a staple of any offensive philosophy because it's easy for the QB to read quickly. It involves two receivers running similar routes of differing depths. It stretches the defense both vertically and laterally.

Slants

Having two receivers on the same side run slants gives the offense a huge advantage. It's similar to the Hi-Lo concept in that it creates two levels of similar progression, but with double slants, there is less depth variance between the two receivers. The first receiver may get open quickly, but if he doesn't, he should drag any extra zone receivers away from the incoming second receiver.

Levels

This works like an inverted Hi-Lo. In this combination, the inside receiver runs deeper, pulling away the safety (and possibly underneath coverage, too), creating an opportunity for the outside receiver.

Flat 7

The Flat-7 is a combination of a flat route, and a 7-route (corner). The safety declares early towards covering the inside receiver, or keeping the top safe, at which point, the corner route breaks outward and leaves him stranded anyway. It's popular because if the safety freezes, then the QB has both options available.

Scissors

Anytime two routes hit a crossroads, you can bet that the offensive coordinator is trying to get defenders to run into one another. In this circumstance, the QBs decision to throw may come longer after the break than usual.

Verticals

Two guys running straight down the field. Depending on the coverage, the outside receiver may have the option to run a comeback route, separating out any 3-vs.-2 scenario that may occur.

Summer School Revision

Offense:

Formations and terminology

Defense:

Understanding the 4-3 defense

Understanding the 3-4 defense