Football is a game of geometry disguised as a game of violence. You see a 200-pound athlete sprinting at full tilt, but what you’re actually watching is a precise mathematical formula unfolding in real-time. At the center of this formula is the wide receiver route tree. It’s basically the foundational alphabet of every passing offense, from Friday night lights to Super Bowl Sunday.
If you don't understand the tree, you're basically watching the game in black and white while everyone else sees it in 4K.
Let’s get one thing straight: the "route tree" isn't some literal drawing of a maple. It’s a numbering system. Most people think receivers just "run open." Honestly? That’s rarely how it works. Every step is choreographed. Every plant of the foot is timed to the millisecond. If a receiver is two yards off his landmark, the quarterback is throwing an interception. It’s that tight.
The Standard 0-9 System: Decoding the Numbers
In most NFL and collegiate systems, the route tree is organized by numbers. Even numbers usually break toward the middle of the field (the "inside"), and odd numbers break toward the sideline (the "outside"). It’s a simple way for a coach to shout "Double Twins Right, 926" and have every player know exactly where to go.
- The 0: Hitch/Comeback. This is a short, 5-to-8-yard sprint where the receiver suddenly stops and turns back to the quarterback. It’s the bread and butter of "West Coast" offenses.
- The 1: Flat Route. A quick 3-step burst followed by a hard 90-degree turn toward the sideline. It’s designed to pull defenders out of the middle.
- The 2: Slant. You’ve seen this a thousand times. Three steps up, then a 45-degree break across the middle. It’s dangerous because it puts the receiver right in the path of linebackers, but it’s the fastest way to get the ball in a playmaker's hands.
- The 3: Out. A 10-yard vertical stem followed by a sharp break to the sideline. This is a "pro-throw." If the quarterback doesn't have a cannon, a cornerback will jump this and take it the other way for six.
- The 4: In (Dig). Similar to the out, but you break toward the middle. It requires serious guts. You’re running into the "wash" where the safeties are waiting to take your head off.
- The 5: Out (Deep). Just a deeper version of the 3.
- The 6: Curl. A deep vertical push, maybe 12 to 15 yards, then a sharp hook back toward the QB.
- The 7: Corner (Flag). The receiver fakes inside and then breaks toward the back pylon of the end zone.
- The 8: Post. This is the home run. The receiver breaks at a 45-degree angle toward the goalposts. Think Randy Moss or Tyreek Hill.
- The 9: Go/Fly. No breaks. No fakes. Just pure, unadulterated speed. Run straight. Catch ball.
It’s Not Just About the Numbers Anymore
While the 0-9 system is the "classic" wide receiver route tree, modern innovators like Kyle Shanahan and Sean McVay have turned the tree into a dense forest. We’re talking about "option routes" and "choice routes" now.
In these systems, the receiver doesn't just run a 4 (In). He runs a "choice" route where he reads the defender’s leverage. If the defender is playing inside, the receiver breaks out. If the defender is playing soft, the receiver sits down in the zone. This requires the quarterback and the receiver to see the exact same thing at the exact same time. If they aren't on the same page? Disaster.
Look at someone like Davante Adams or Justin Jefferson. They aren't just faster than everyone else. They are masters of the "stem." The stem is the first 5-10 yards of any route. A great receiver makes every route look like a "9" for the first ten yards. The defender gets scared of the deep ball, starts backpedaling, and then—snap—the receiver breaks off a hitch.
That’s the "illusion of complexity." You use a simple wide receiver route tree to create infinite problems for a defense.
The Evolution of the "Tree" Concept
Back in the day, Don Coryell (the father of "Air Coryell") really formalized this numbering. Before him, routes had names like "The Sideline" or "The Square-In." By giving them numbers, he allowed for faster communication. It changed football forever.
But here is a nuance most fans miss: the tree changes based on where the receiver is lined up. An "X" receiver (the split end on the line of scrimmage) has a different tree than the "Z" (flanker) or the "Y" (tight end).
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For example, a "7" route for a slot receiver is often called a "7-bracket" or a "seam-read." It’s the same basic shape, but the geometry of the field changes the timing.
Why Success Rates Vary by Route
Not all routes are created equal.
Statistical analysts often look at "Success Rate" per route. Generally, "Slants" (2) and "Hitches" (0) have the highest completion percentages because the throws are short and the windows are clear. However, "Go" routes (9) have the lowest completion percentage but the highest "EPA" (Expected Points Added).
You’re basically gambling. Do you want the safe 5 yards of a hitch, or do you want to take a 20% chance on a 40-yard bomb? The best playcallers, like Andy Reid, use the short routes of the wide receiver route tree to "set up" the deep ones. They’ll run the "Out" three times in a row until the cornerback starts cheating toward the sideline. Then? Double move. Out-and-go. Touchdown.
The Lost Art of the "Double Move"
Speaking of double moves, these are the "branches" of the tree that aren't numbered 0-9. You’ve got the "Sluggo" (Slant-and-Go). You’ve got the "Out-and-Up."
These are high-risk, high-reward plays. They take a long time to develop. The offensive line has to hold up for four or five seconds—which is an eternity in the NFL—while the receiver sells the first part of the route.
If the receiver doesn't "sell" it with his eyes and hips, the defender won't bite. This is where the "human" element beats the "AI" element of scouting. You can track a player's speed with GPS chips, but you can't easily track how well he "fakes" a slant with a shoulder shimmy.
Breaking Down the "Post-Corner"
The "Post-Corner" is one of the hardest routes to cover in existence. The receiver stems vertically, breaks toward the goalposts (the Post), waits for the safety to commit his hips to the middle of the field, and then violently plants his outside foot to break back toward the sideline (the Corner).
It’s a nightmare for defensive backs. If you’re a DB, you’re taught to "protect the inside." When you see that post break, your instinct screams at you to follow. But the moment you do, you’re dead.
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How to Watch the Tree Like a Pro
Next time you’re watching a game, don’t just watch the ball. Seriously.
Watch the "X" receiver (the one isolated on the weak side). Count his steps.
1, 2, 3... Break.
If he breaks on the third step, it’s a quick-game route.
If he’s still running at step five, something deep is happening.
Also, look at the "alignment." If a receiver is "nasty" (lined up very close to the offensive tackle), he’s probably running an "Out" or a "Corner." He’s giving himself more room to work toward the sideline. If he’s lined up wide, almost touching the white paint of the sideline, he’s almost certainly running an "In," a "Slant," or a "Post." He’s using the width of the field to his advantage.
Common Misconceptions About the Route Tree
People often think "speed" is the most important factor for a 9-route.
Wrong.
It’s "tracking."
There are plenty of guys who run a 4.3-second 40-yard dash but can't catch a deep ball because they can't track it over their shoulder while sprinting. Conversely, some "slow" receivers (guys in the 4.5 or 4.6 range) are elite deep threats because they understand how to use their body to "box out" the defender like a basketball player.
Another myth? That the wide receiver route tree is the same for every team.
It isn't.
In the "Air Raid" system (think Mike Leach or Lincoln Riley), the tree is much more fluid. It’s based on "grass." The receiver just runs to the open space. If there’s a defender in the "hook" zone, the receiver moves to the "curl" zone. It’s less about a numbered diagram and more about "spatial awareness."
Compare that to the old-school "Earhardt-Perkins" system used by the Patriots for years. That system used "concepts" where a group of three receivers ran a combined pattern (like "Snag" or "Tosser"). The individual numbers mattered less than the overall shape of the play.
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The Physical Toll of the Tree
We don't talk enough about the footwork.
To run a "Dig" (4) at NFL speed, you are putting an incredible amount of torque on your ankles and knees. You are essentially trying to go from 20 mph to a dead stop, turning 90 degrees, and accelerating again in under a second.
This is why "Route Running" is a specialized skill. You see guys like Cooper Kupp who might not win a track meet, but their "braking system" is elite. They can stop faster than the guy chasing them. That's the secret.
Actionable Insights for Players and Fans
If you’re a young player or just a die-hard fan trying to understand the "why" behind the "what," here is how you master the logic of the passing game.
First, stop thinking about routes as lines on a page. Think of them as timing triggers. A "3" route is timed to a 5-step drop from the quarterback. If the QB takes three steps and hits the last one, but the receiver is still in his stem, the play is dead.
Second, pay attention to "Leverage." If a defender is playing "Outside Shade" (lining up toward the sideline), he is literally telling the receiver: "I will not let you run a 1, 3, 5, or 7." He is forcing the receiver inside toward his help (the linebackers). A great receiver will use a "mandatory outside release" to force that defender to turn his hips, even if the route is actually a "Post" (8).
Third, understand the "Red Zone" tree. The field shrinks. The "9" (Go) route becomes almost useless because you run out of end zone. In the Red Zone, the tree transforms into "Fades," "Slants," and "Shovel" concepts. The "Corner" (7) becomes the deadliest weapon because it uses the back corner of the end zone—the one place a defender can’t get help from a safety.
Next Steps for Deepening Your Knowledge:
- Watch All-22 Film: If you have access to "Coaches Film," watch the game from the high-angle end zone view. You’ll see the wide receiver route tree develop in a way the broadcast view never shows.
- Study the "Tree" Variations: Research the differences between the "Coryell Tree" and the "West Coast Tree." You'll notice that while the numbers are similar, the depths and "break points" vary wildly.
- Track "Target Share" by Route: Look at advanced stats sites (like Pro Football Focus or Next Gen Stats). See which receivers thrive on "In" routes versus "Out" routes. It will tell you everything you need to know about their physical limitations and strengths.
Football isn't just a game of "catch." It’s a game of "where" and "when." The route tree is the map that tells the players how to get there. Once you see the numbers, you can't unsee them. Every play becomes a story. Every incompletion becomes a "why." And every touchdown becomes a masterpiece of geometry.