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Defining Defensive Terms

A primer on concepts and terms I'll use when discussing our defense and opposing offenses.

John Reed-USA TODAY Sports

Barring one afternoon I helped a friend run blocking and tackling drills for a little league team, I last wore a whistle eleven years ago.  Spread offenses were just starting to take off back then.  Rich Rod and Tommy Bowden were running an early version at Clemson.  Alabama's and Arkansas's offenses had some elements of a shotgun running attack that savaged Auburn in the early 2000s.  On the other extreme, spread air attacks at Purdue, Louisiana Tech, and Texas Tech were starting to revive and reinvent old run-and-shoot theories.  But for the most part, teams ran the same offenses that had been popular since the early to mid 80s when the wishbone started to die.  There was a lot of I, offset I, and single I looks in college.  The dominant offense was being run by Steve Spurrier whose offenses passed to set up the run mostly from under center.  Wing T, veer, and I were dominant in high school.  We didn't have a name for many of the formations spread coaches run today.  All that to say, it's been a while and I'm a bit rusty.

The good news is, formations are just window dressing.  The plays and theories behind the plays remain the same.  No matter what crazy formation an offense throws out there, there is a balanced defensive formation.

I want to build off the last article with a series of articles on Auburn's defense.  The first challenge is making sure we all speak the same language.  Below, I will discuss general terms for offensive personnel groupings, defensive front alignment, and coverages with pictures to give you an idea of what we're talking about.  Again, for those who already know and understand these terms, please be patient while we set this up.


The first challenge a defense faces is getting the right personnel on the field.  As discussed in the first article, offenses are proactive, defenses are reactive.  A defense doesn't know what play the offense is going to run (unless it has one of its opponent's former assistants stealing the opponent's signs . . . allegedly ;) ).  But a defense can start to narrow down what play it is likely to see by seeing what personnel the offense has on the field.  Defenses label personnel with a two digit number.  The first digit is the number of running backs and the second is the number of tight ends.  For example, a traditional I formation with a tailback, fullback, two wideouts, and a tight end would be 21.  You don't need to list the number of wide receivers and quarterback because it's implied.  There are six skill position guys and five linemen in almost every formation.  One of the six skill guys is a quarterback, so RB+TE+WR=5.  If you know the number of running backs and tight ends, you also know the number of receivers.  The personnel on the field is a major clue to what formation and play you're likely to see based on your film study.

I say all this because when I talk about Auburn's defense, opposing offensive personnel will determine ours.  Washington State ran a lot of 10 personnel with a single running back.  Auburn, which has a 4-2-5 base, spent a lot of the day with three down linemen, a linebacker/safety standing up on the line, and a single linebacker playing fairly deep.  Alabama tried to bow up on short yardage with a 23 or 32 personnel and Auburn had seven men on the line and three others in the box within three yards of the line of scrimmage.


A defense defines an opposing offensive line two different ways.  First, the holes between the linemen are gaps.  These gaps are labeled with the letters A-D moving from inside the line to the outside.  Run defenders have gap responsibility.  Defensive alignment is defined by a numbering system starting with 0 head up over center and moving outward.  Don't ask me why the numbers are out of sequence outside the tackle box.  And don't ask why I'm so terrible with Paint.  We can't all be Thujone.

There are other numbering schemes but this is the one I used and the one I will use to describe our fronts. Click for a larger version.



There are many different types of coverage but they break down into two main types, man and zone. In man coverage, defenders are responsible for specific receivers.  In zone, a defender covers an area and any receiving threat which enters that area.

It's not always easy to tell the difference between man and zone coverage.  Within a zone, defenders will use man-to-man cover techniques and sometimes in man-to-man players may swap receivers so that it looks like a zone.  Also, presnap, a defense may show a certain look but move into their actual coverage either at or just before the snap.  What follows is a list of common coverages.  This list is not meant to be exhaustive.

Coverages are usually defined by how many defenders are assigned to the deep zones.  For example, Cover 1 means there is one free safety giving help deep.  Cover 3 means there are three defenders deep.  Fewer deep defenders give offenses the chance to stretch the field vertically.  More deep defenders let offenses spread the field horizontally in shallow and mid-range routes.  The reason for this of course is that you only get 11 defenders.  If you gave full coverage to both the five shallow zones and four deep zones, it would leave the defense too open to the run.

Cover 0 is the purest form of man to man.  There is no deep safety.  If a receiver gets separation from his defender, the cavalry isn't coming.  This type of defense risks the big play.  To compensate for this risk, the defense usually brings a max blitz with more defenders than the offensive line can block.  This way, the quarterback should have to get rid of the ball quickly, forcing an inaccurate throw, sack, or quick completion, minimizing the risks associated with a Cover 0.  Here is a picture of a Cover 0 with accompanying blitz the fine people at Roll Bama Roll had with a preview of Oklahoma's defense.



Cover 1 tends to be a man-to-man defense with one free safety looking for receivers streaking down the field that he can help cover.  Here is a drawing of a cover 1 man alignment from Mile High Report:



Cover 2 has two deep safeties.  Cover two is commonly run with both a zone under (usually 4-6 shallow zones with two deep safeties) or a man under.  This picture shows a cover 2 with man-to-man or man under coverage of the receivers from Arrowhead Pride.



Bleeding Green Nation shows the assignments in a pure zone Cover 2.



Cover 3 has three deep safeties and is almost exclusively a zone coverage except for some prevents. Here is what a cover three looks like as drawn by Coug Center:



Cover 4 has four deep safeties and is almost exclusively zone except for some prevents.  This image from Niners Nation shows how a defense, which looks like either a cover 2 zone or man cover 1 presnap can move to a cover 4 after the snap with both safeties and both corners dropping into a deep zone.



In future posts, we'll expand on these concepts more as it applies to Auburn.