All 22 of Seahawks Cover 3 Defense

In preparation for Super Bowl XLVIII we are breaking down the key match up, Peyton Manning vs the Legion of Boom. While everyone and their mother seems to have an opinion on what will happen Sunday, we want to show you what makes the Broncos offense and Seahawks defense so dominant with a quick film study using all 22 film. Today, we examine how the Seahawks have transformed a basic Cover 3 defense into the league's best by using their physicality and aggression at every level of their defense.

While Denver’s offense has received the majority of attention leading up to Super Bowl XLVIII for rewriting the record book behind Peyton Manning's brilliance, Seattle’s defense has been almost as dominating. Somehow in today's pass happy era where 300 yard passing performances and 3 touchdowns are the norm, the Seahawks have smothered opposing offense holding them to 172 pass yards per game and under 15 points, good for the 10th best defense based on some advance metrics.

The Seahawks defense, like all defenses, starts with their front where they play 1 gap system focused on gaining penetration instead of controlling the line of scrimmage. The problem with a true 1 gap system is most offensive formations have 8 gaps and only 7 defenders to fill them. To even the numbers Pete Carroll and the Seahawks simply bring their strong safety into the box and played a 4-3 under forming a 6-2-3 of sorts with 8 defenders in the box.

Here is an example of how those 8 defenders, actually 9 in this case, account for every gap against a heavy formation. Note the 6 defenders at the line of scrimmage.


And here is an example against a spread offense, something similar to what Denver should present to them.


Behind this aggressive front, the Seahawks match the back of their defense to the front by playing press coverage and challenging their opponent’s receivers from the snap. Not only does this prevent quick throws and disrupt the timing of the offense, it fits perfectly with their physical defensive identity.

With their hyper aggressive alignment, especially playing with a single high safety the majority of the time, the Seahawks rely on a Cover 3 coverage. While it lacks sophistication, it's proven effective even against today's high octane offenses, relying on their corners to funnel the receivers towards the single safety and their underneath zones being able to attack the underneath throws while dropping enough to squeeze the space between the levels of the defense.


First, let’s look at how the Seahawks big physical corners are perfect for redirecting the outside routes towards the best safety in the league, Earl Thomas.


While this throw ended up being picked off by an underneath defender, the two deep routes, which were the primary reads, were completely smothered by the Seahawks secondary and were the root of the problem for the offense. With the timing of the play off and the pass rush closing in, Kellen Clemens was forced to throw a check down in the middle of the field, where 4 defenders were waiting to break on the football.

As we saw on that last play, the underneath zones are ready to pounce on anything in front of them and with a group of hard hitting linebackers and Kam Chancellor patrolling the middle of the field, the Seahawks can make their presence felt.


And that is why they call them the Legion of Boom. Again the Cover 3 defense allows the Seahawk defense to do what they do best, play downhill and knock the snot of out receivers.

Not only can the underneath zones act as enforcers over the middle of the field, they can drop deep enough to take away intermediate routes even along the sideline.


While this is a bad read by Kaepernick resulting in a pass that should have never been thrown, it highlights just how effective the underneath zones are against intermediate routes. Without any threats in front of him Chancellor simply continued his drop reading Kaepernick’s eyes and took away any intermediate route along the left sideline.

The final piece of the puzzle for Seattle’s pass defense is their ability to win at the point of the catch.


On this ill advised throw to a Go route by Kaepernick, the 6'3 Sherman shows his excellent body control to turn and make a play on the football before the receiver can, a skill that allows the Seahawks to leave their corners without any help on the outside. And that is really the key to the Seahawks defense, their secondary consistently wins one one one match ups allowing them to be hyper aggressive at the line of scrimmage.

All in all the, Seahawks defense is a force to be reckoned with, and we didn’t even get to examine their frightening pass rush either. Through their aggressive 1 gap scheme and reliance on their elite secondary, the Seahawks have transformed a simple Cover 3 into the most dominant defense since since the Ravens of the early 2000's.

Luckily for football fans the last remain hurdle for what could be a all time great defense is the Sheriff himself, Peyton Manning. Having torched the league for 54 touchdowns and nearly 5,500 yards, Manning will not be intimidated by Richard Sherman and Co. at all. Instead he will bring the NFL's best offense of all time and find out if whether defense really wins championship or if the NFL has fundamentally changed.

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