X's & O's: Breaking Down Justin Gilbert's Pick Six Using Trap Coverage

The sophistication of modern-day passing attacks has forced defensive coordinators to become more creative in coverage design and disguise. The OBR dives into ‘trap coverage’ concepts with a look at the biggest play of Cleveland Browns’ cornerback Justin Gilbert to date, a highlight-reel pick six courtesy of Andrew Luck that came off a beautifully designed and executed ‘trap flat’ concept.

Base pass shells like Cover 1, Cover 2, Cover 3, and Cover 4 are too limited to stop the college and NFL passing game in this age of offense. Creative offensive minds have identified and ruthlessly exploited the weaknesses in the various coverage groups using triangle (and rub concepts against man defense) that vertically and horizontally stretch defenders, creating defined progression and reads for the quarterback. Any offensive coach worth his (or her) salt has several ‘coverage beaters’ in the playbook that take advantage of schematic weaknesses within all of the aforementioned coverage families (think the ‘smash’ concept against Cover 2 or the curl-flat against Cover 3). Most defensive coordinators have integrated ‘pattern matching’ rules into their defenses that require the pass defenders to read the receiver’s release at the line of scrimmage to determine who guards who (like a matchup zone in basketball) to counter ultra-efficient offensive play calling, but even modern-day pattern matching rules can be defeated with creative route design. How do defensive coaches counter these concepts while maintaining tried-and-true base coverages? The answer lies in trap coverages.

Trap coverage has been used up and down the college ranks for a number of years, but only within the last half-decade have we seen widespread matriculation into the NFL coaching ranks. College coaches like TCU Gary Patterson (whose Blue Special and Two Read are likely the most popular versions of trap coverage at the movement) have led the charge in modifying coverage rules within base concepts like Cover 4, both preserving the basic integrity and rules of the defense while changing individual rules and responsibilities. Trap coverages rely on three principles:

  • Disguise the coverage pre-snap
  • “Show” the quarterback a specific coverage before rotating to something different after the snap 
  • Change the ‘usual’ read rules that determine individual responsibility after the receivers release at the snap

Gilbert’s pick-six of Andrew Luck provides a great example of all three principles in action. Without further ado, let’s go to the tape.

Nursing a seven-point lead with ten minutes to go in the 3rd-quarter, the Browns’ defense has Luck facing a second-and-ten from his own 12-yard line. The down and distance make this a likely pass, creating a great opportunity to set a trap. Pettine takes it one step further by running the trap behind a slot blitz from the field defensive back (most teams will slot blitz from the boundary side as the defender has less distance to cover). This is likely by design in order to force Luck’s eyes to the trap side as it is now has one less pass defender and any built-in hot routes will be to that side.

The Colts’ offensive is aligned in a Trips right look with the tailback ‘Lo’ (to the left of the quarterback). The defense is showing a single-hi safety in the middle of the field, narrowing the likely pass shell down to Cover 1 or Cover 3. In addition the right and left cornerback are aligned 7-8 yards off the ball with their backs pointed towards the sideline, again signifying Cover 3 or off-man.

Now that the front and coverage have been set, let’s breakdown ‘trap flat’ coverage. The idea is to ‘show’ Luck Cover 1 behind the blitz (across the board man defense with a single deep safety to protect the post) after the snap, when in fact the coverage plays out like Cover 0 (no deep safety help) with a defensive back coming off his man to rob any throws into the strong side flat area.

Gilbert will carry the #1 wide receiver 8-10 yards down the field, and then pass him off to the free safety who will play him in man (known as ‘topping the route’). Once Gilbert passes off the vertical from #1, he will zone turn with his back to the sideline in order to read the quarterback’s eyes and look for any out-breaking routes coming his way. If the quarterback throws the ball to anything outside –breaking (like an out or flat route) Gilbert will be in perfect position to rob the throw.

The right cornerback will play the boundary receiver using a MEG (Man Everywhere he Goes) technique. He is playing off-man coverage here as there is over-the-top safety help. Because the free safety will top anything vertical by the strong side #1, the cornerback is in Cover 0.

The linebackers will use a ‘cut’ technique on the #2 and #3 receivers, playing both from inside leverage and cutting any outside-breaking routes. In a normal Cover 1 this would put both defenders in a poor position to play the pass because their leverage and the receivers’ break to the outside creates natural separation, but the cut technique actually encourages the quarterback to throw the ball into that area because the nine route from #1 should have cleared Gilbert out. Unfortunately for Luck Gilbert is still there waiting to spring the trap.

There are a lot of moving parts here so we will break things down one at a time.

The Colts are running an OVS (Outside Vertical Stretch) concept, or ‘flood’, using a clear out route from the #1 receiver, a pivot route from the #2 receiver, and a sped out from the #3 receivers. These types of flood concepts are very effective against zone defenses, but the pivot route from the #2 receiver also makes this a nice man-beater.

First, notice the linebackers open their hips towards and bail towards the three-receiver surface. Again, their leverage allows them to catch and carry any vertical (like a seam) or in-breaking routes (like a shallow or dig), while putting them in position to cut any outside-breaking routes into the trap.

We can already see Gilbert’s eyes in the backfield (where they should be) and the free safety hauling across the field to top the #1 receiver if he continues to run vertically.

Moving along Gilbert has released his man to the free safety and continues to eye the quarterback. It is important to note that Gilbert IS NOT free lancing here. Much like a soft Cover 2 corner his job is to pass off vertical routes, read the quarterback, and jump any routes that enter the flat.

We can see the separation created from playing the speed out from inside leverage at the 25-yard line. Remember this is a trap; the defense wants Luck to see the separation and target this route. If the ball is thrown the receiver will have to make the catch with the linebacker closing from the inside and Gilbert closing from the outside, there will not be much room to squeeze the ball through.

Although Luck is obscured by the blitz, the ball has just come out of his hands. Gilbert is quickly closing on the speed out looking to make a play on the ball. At the very least he should be looking at a pass breakup, if not more.

The Oklahoma State product gets a great jump on the throw, catches the ball, and shows his open field athleticism on the way to six points.

Circling back to our principles of trap coverage, we can see all three tenants in action:

  • Show Luck Cover 1 pre-snap
  • Blitz the field defensive back/rotate the safety to the three-receiver side to continue the man-coverage charade and force Luck’s eyes to the trap-side where he should see ‘separation’ from the #2 or #3 receiver
  • Convert Gilbert’s man coverage to a zone post-snap with the free safety picking up his man

Good coaches put their players in position to succeed, and while the Pettine/O’Neil regime’s shortcoming are too numerous to list here, Browns’ defensive coordinator Ray Horton should take a page from their playbook in order to get production out of Justin Gilbert before it’s too late.


The OBR Top Stories