The following excerpt is taking from a comprehensive post breaking down Browns’ cornerback Justin Gilbert’s 2014 pick-six off Andrew Luck. The entire article can be read at The Orange and Brown Report…
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 explosive 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.