clock menu more-arrow no yes mobile

Filed under:

Summer School: Defensive line techniques and introducing the secondary

This week we finish off the defensive front and begin to turn out attention to the defensive secondary.

In the first two installments on the defensive side of our Summer School series, we looked at the evolution and current implementation of the 4-3 and 3-4 defensive fronts. Those two articles covered most of the basics of defensive fronts in the NFL. However, there is one last thing to go over before we can move on to the defensive secondary.

Defensive Line Techniques

To avoid confusion, I referred to the positions by name rather than their alignment. However, when it comes to defensive line parlance, where a player lines up with respect to the offensive line matters. Where a defensive linemen lines up, and which gap he attacks, is referred to as his "Technique."

Defensive line "techniques" are often confused with the technical aspects of an individual player's position. However, when talking about alignment, "technique" isn't in regards to hand usage, leverage, or pass rush moves.

The above diagram is the now-familiar 4-3 Under front (chosen because it is the Giants "base" defensive alignment).

Already recognizable are the defensive end, defensive tackle, nose tackle and linebacker positions, as well as the gaps for which they are responsible [the red arrows pointing to the yellow letters]. What is new this week, are the "technique" designations, identified by the red numbers in front of the offensive linemen. With these numbers we don't have to simply refer to a player by his position, but are able to identify specifically what role he is playing in the defensive front.

In this naming system, the even numbers directly in front of the offensive lineman indicate that the the defender lines "head up" on that particular lineman. The most common is the "0-Technique" or pure 3-4 Nose Tackle, who lines up directly in front of the center, and is responsible for controlling both "A" gaps. The odd numbers to the outside of the offensive linemen indicates that the defender is on the outside shoulder, while the 2i or 4i indicates that they are shaded towards the inside. Some places use a slightly different numbering system, dispensing with the "i" designation and counting outwards from "0" to "9" technique, but this was the system used under Tom Coughlin, and we don't have any indication that it is changing.

So, in the 4-3 Under, the right defensive end is properly called the "7-Technique" (often shortened to 7-Tech), because he lines up off of the tight ends' inside shoulder. The defensive tackle is lined up as the the "3-Technique", the position made famous by Warren Sapp and John Randle, while the nose tackle in this front is the "1-Technique". The left defensive end is lined up at the "5-Technique", showing how -- in some ways -- how little difference there is between a 4-3 Under and a 1-gap 3-4. At the end of the front is the outside linebacker, usually called the "SAM", but since naming can vary by coach, we'll just leave it as "OLB". If he is playing downhill, toward the line of scrimmage, he would be playing the "9-Technique."

There are variations on the 4-3 front that line both defensive ends at the "9-Tech", an alignment called the "Wide-9" defense. It is used by defenses all over the league, but is most commonly associated with new Philadelphia Eagles defensive coordinator, Jim Schwartz. While other defensive fronts try to be at least competent in everything, the Wide-9 comes with a distinct advantage in the pass rush, while also having a distinct disadvantage in run defense. By aligning both defensive ends with the tight ends' outside shoulder (or where they would be if the offensive formation has a tight end on that side), it creates a very good angle for the pass rusher to get to the quarterback, putting tremendous stress on the offensive tackle to create a pocket.

However, by stretching the defensive line so widely, it creates natural running lanes for interior runs. Unless a defensive front has a pair of very good defensive tackles to go with athletic and stout linebackers, the defense may well give up running alleys in the middle.

With that final piece in place, we can wrap up the discussion on the defensive line -- at least for now -- and move on to the secondary.

Introducing The Secondary - Terms and Positions


Man Coverage: Simply put, Man Coverage has a defensive player lining up across from an offensive player and covering him. Generally, there are two forms of man coverage, Press-Man and Off-Man coverage. Man coverage corners need to have the athletic ability to stay with receivers throughout the entire route tree, turning and running with them without losing their position. Man coverage often puts the defender at a disadvantage when it comes to defending the run or screen plays because the receiver is already in position to block.

  • Press-Man coverage sees the defender physically disrupting the receiver at the line of scrimmage, trying to re-route him or disrupt the timing of the route. At the NFL level, defenders can only have their hands on receivers within five yards of the line of scrimmage, or it is considered pass interference.
  • Off-Man coverage has the defender in man coverage, but retreating into coverage off the snap. Off-Man coverage can be incredibly difficult to play at the NFL, because the defender must be aware of where the rest of the secondary, the receiver and his route, and the defensive play call. All of that influences how he drops into coverage.

Zone Coverage: Where Man Coverage has the defender covering a specific player, zone coverage asks the defender to cover an area of the field. Zone coverage stresses communication, discipline, and awareness over raw athleticism on defense. By covering an area of the field instead of a player, the defender can have his eyes in the backfield and is more likely to capitalize on mistakes from the quarterback, as well as putting the defender in better position to defend run or screen plays. On the down side, zone coverage makes stopping quick passes problematic at best, and can be defeated with route combinations. Also, breakdowns in communication or assignment discipline can lead to huge plays for the offense.


Boundary Corners -- Boundary corners are among the most sought-after defenders, with the best being considered one of the four "cornerstone" (no pun intended) positions along with quarterback, offensive tackle, and pass rusher when it comes to team building. The best boundary corners are able to play any coverage technique, but most are limited to man or zone, either by their mental approach or athleticism. The prototypical corner should have the speed to run with fast receivers, the size to match up with bigger receivers, quick feet and fluid hips to change direction easily, and the awareness to make a play on the ball when it comes their way. They are also often called upon to "finish off" outside runs that the defensive front has strung out, so run defense is important. While he is untested in the NFL, Giants' rookie Eli Apple has all the physical traits teams look for in a boundary corner.

Slot Corners -- Slot corners, though "slot defenders" might be the better term, are generally smaller and quicker than their their outside counterparts. Slot corners are usually responsible for covering the middle of the field, and may be the most important defender on third down, when a slot receiver can be the quarterback's first target. While they can be in man or zone coverage, offensive alignments generally keep slot receivers off the line of scrimmage, preventing press-man coverage. They must, however, be ready to deal with bigger receivers, or even outside receivers who get moved inside to create a mismatch.


Free Safeties -- The "Free" safety is often the defense's last line of defense against vertical passes, and is one of the most difficult positions to play. They must be athletic enough to cover large amounts field, play man coverage, or even come down as a slot defender a la Tyrann Matheiu or Antrel Rolle. Free safeties are also (generally) the "quarterback" of the secondary, working in concert with the middle linebacker to relay the play call to the other secondary players and get them lined up properly, as well as communicate any changes. He must also have a sound knowledge of offensive concepts so he knows which receiver will need to be double covered. Ed Reed or Earl Thomas are the prototypical free safeties.

Strong Safeties -- Strong safeties are the "enforcers" of the secondary, the role that now falls to sophomore Landon Collins. Their job is to play close to the line of scrimmage with players 20, 50, or even 100 pounds heavier, defending the run or covering tight ends, running backs, or even receivers. As spread offense concepts continue to seep into the NFL from college, the role of strong safeties evolves. In some ways, the line between strong safeties and weak-side linebackers is blurring. Many defenses are beginning to feature safety/linebacker "hybrids," to increase the speed and athleticism of their defense while sacrificing as little size and physicality as possible.