The Detroit Lions started the 2011 season with a roar, winning their first five games out of the gate before fading in the weeks to follow. But they recovered with a big comeback performance against Carolina on Sunday. With that, they’ve gained some momentum back heading into arguably their biggest game of the season. In an attempt to shed some light on what to watch for Thursday, when the Lions host the undefeated Green Bay Packers on Thanksgiving, let’s take a step back and analyze the Lions’ biggest play from the Carolina matchup — a game-clinching interception from the recently-acquired Chris Harris.

Coming on to the field for what would be the final drive of the game, quarterback Cam Newton and his offensive teammates opened up just inside the 22-yard line in their own territory. They came out in a spread formation with 11 personnel, which is one running back and one tight end and three wide receivers. On this specific play, the three wide receivers and the tight end were spread out in a Doubles set, which is two pass catchers to each side of the formation.

To counter this, the Lions defense came out in their 40 Nickel package. The ’40′ number designates their front, which means there are four defensive linemen. A ‘nickel’ package is identified as five defensive backs, mainly a slotback (or “slot corner”) replacing a linebacker to match up with the slot receiver at the bottom of the screen.

At the snap of the ball, the Panthers’ pass catchers ran a series of routes, but two key routes helped set up the main concept , which is simply known as the “Post-Dig.”

The Post-Dig pass concept is as it says, a Dig route which requires a pass catcher, in this case X, to explode vertically and take a stem of 10-15 yards (depending on the coaching staff’s teachings) before breaking the route inside and over the middle of the field. On the other side of the field, the Z pass catcher pictured will take a vertical stem before breaking the route off  between 10-12 yards and inside to the middle of the field, thus creating a Post route.

(image courtesy of shakinthesouthland.com)

This concept is typically effective against Cover 2 and Cover 4 (out of play action), as it brings up one of the safeties which allows the quarterback to throw the Post route in behind him. If the safety stays deep to cover the Post, the Dig route over the middle is often open when the MIKE (middle linebacker) comes up to deal with the check-down out of the backfield.  However, in the Carolina’s case, they ran this out of their Doubles formation and simply flipped the routes, with the Post ran on the left side of the formation and the Dig on the right.

To counter this concept, Lions defensive coordinator Gunther Cunningham called, albeit in a much fancier way, the Tampa 2 coverage. The Tampa 2, which is one of my favorite coverages in all of football, was initially developed to defend the short passing game of teams in the early 1990s. As Tony Dungy described in his book, Quiet Strength, it was a modification of the Cover 2 and a blending one-high principles.

One-high principles are seen every Sunday, as teams often operate out of the most used coverage in all of football, Cover 1 (a.k.a Man-Free). Another form of one-high coverage is Cover 3. In the early nineties, Cover 3 was one of the most popular coverages used because it allowed teams to defend the deep ball while having an extra defender in the box. Both of these coverages have one thing in common — a single defender in the deep middle of the field.

Two Vikings defensive minds–Dungy and linebackers coach Monte Kiffin–were instrumental in developing the Tampa 2, a zone-based coverage that Dungy preferred. The Tampa 2 was much like the Cover 2, with two deep safeties defending the deep levels of the field, two outside linebackers responsible for the Hook areas and two cornerbacks that were Flat defenders. However, there was one significant difference: the middle linebacker’s drop.

The middle linebacker in the Tampa 2 drops down the deep middle of the field, covering anywhere between 15 to 25 yards, consequently splitting the deep responsibilities with the safeties into thirds.

(image courtesy of ESPN.com)

At the snap of the ball, the Lions defenders ran to their landmarks, which are strongly emphasized, along with fundamentals, in the Tampa 2 coverage. Middle linebacker Stephen Tulloch is seen dropping with his shoulders pointed in the direction of the tight end while simultaneously reading the quarterback’s eyes. Meanwhile, the slotback and outside linebacker are seen dropping to their designated ‘Hook’ landmarks, and the cornerbacks buzz their feet in the flats.

When Newton shifts his eyes from right to left, so does Tulloch, and because of this he is able to disrupt the passing lane. However, Newton is a young quarterback that will make some mistakes and trust his arm too much, which gets him in trouble. That was the case on this play, as Newton attempted to fire a throw into tight coverage over the middle of the field to his receiver who was running the Post route.

Last but not least, Tulloch is able to get his hand on the pass as it comes toward the middle of the field and into his designated area. He made the deflection, and Harris was in the right spot to secure the interception.

Cunningham made a good call here going with the Tampa 2 coverage to fend off any potential late game dramatics created by a Panthers’ score. With many offenses throwing a lot of short passes and using three-strep drops, this coverage continues to have a place in defensive playbooks, as it creates turnovers on a consistent basis.