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By Mike Kuchar

Senior Research Manager

X&O Labs



It’s that time of the year when offenses are either being constructed or retooled, so we felt there was no better timing than now to release our latest study on defensive identifiers.  The following information is based on a collection of surveys designed towards offensive coaches in an attempt to decipher the progressions used in three major defensive identifiers- front, second level players and coverage.  While we realize all programs may have different methodologies in uncovering these structures, our goal was to find and provide a common denominator for each.


Case 1:  Identifying Defensive Front

Question 4

The first part of any identification systems seems to be recognizing the defensive front and more importantly which player makes the call to do so.  Our research was split down the middle when deciding which player makes the front identification call.   According to our research, 53.6 percent of coaches will have their Center make the call to recognize front while 22.6 percent will have their QB handle that responsibility.   Rich O’Connor, the offensive coordinator at Montclair State University (NJ) has his Center’s make all the checks for two main reasons- he’s usually more versed in studying defensive fronts and it’s just another thing that QB’s don’t have to worry about.  "Our QB is asked to do a lot in our system, so we just felt that this is something the Center can handle," says O’Connor.  On every snap, he’ll have his Center make three calls: identify the front, identify the Mike LB and then give the box count (the amount of players in the tackle box).

We also had a good faction of coaches split the responsibility between the Center and the QB.  "The quarterback and center both have a role in identifying the front. The center is going to make an odd or even call, and identify the Mike," said James Vint at Cornado High School (TX).  "The QB is going to identify and communicate the "Q" player. The Q player is the defender the quarterback is responsible for in our option schemes."   Some coaches, particularly at the high school level, will even let their most experienced offensive lineman handle the call.   Others will also have their running back make the call for the skill players.   Regardless of the call, 82.1 percent of coaches surveyed will always identify the defensive front on every snap.

We’ve found that 29.9 percent of coaches use a combination of a numbering system and a name system to identify defensive fronts.   A numbering system mainly refers to the technique of the first level defenders, which would read from left to right.  So in an even front a 13 front would resemble a one-technique or shade to the left and a three-technique to the right.  If the number were 31, than a three-technique would be to the left side while the shade or one technique would be to the right.   Some coaches, particularly spread system coaches even use a color system to indicate where the three-technique is in an even front.  For example, the "red" side may denote the side of the three technique, while the "white" side may be the shade side.    One of the coaches who took our survey verbalized how he identifies an even front.  "When we are facing an even front team the Center will ID the 3 tech with a "red" or "blue" call then he will ID the Mike linebacker twice.  If the defense aligns with a two-technique, the C will make a DEUCE call, then ID the MIKE.  If the defense aligns into an Over front the Tackle that has the ghost 9 tech will make an OSCAR call to the C, the C will repeat and ID the MIKE.  When facing a 34 team the Center makes an OKIE call, then IDs the Mike.  When facing a 33 Stack - the Center makes a "Stack: call, then IDs the Nose guard with a "Zero" technique call.

When we researched this further we did find that 87.5 percent of coaches don’t deviate from a shade and 3-technique side against four down fronts mainly due to the multiplicity that defenses present by pre-snap stems and post-snap movement.   So what is the benchmark number of fronts that offenses should be identifying?   What is too much?  The base number seems to be three or less- 61.9 percent of coaches only use up to three identifications while 34.9 percent use between 4-7 identifications.   Offenses are not trying to limit their verbiage in identifying fronts.  Now, we’ve found that spread teams are simply identifying only the bubble (a gap not accounted for by a first level defender) for zone techniques. They will only use two names and cut the ball in half if either you have an open B gap or a closed B gap.   " Our Center ID's front based on where A & B gap defensive linemen are aligned," said Coach Hagebusch at Nowata High School (OK).  "Next he ID's the MLB or the LB most likely to blitz to help with pass pro."

Coach Hopkins at Basehor-Linwood High School (KS) follows the same methodology.  "We only say odd or even. We really don't consider it "odd" unless there is a true zero-technique Nose guard and we don't care if there are two or three linebackers," said Hopkins.   "Due to stemming by linebackers, we don't focus on names such as Eagle, Bear, etc."   We did find coaches like Bryan Moore at Heidelberg College who will only identify the front if it is a Bear front-which denotes a zero technique Nose guard and two three-techniques.   Rick Wimmers at Fishers High School (IN) believes in the same simple methodology.  "The Center IDs all fronts as either 3 Down (1 defender in A & B gaps), 4 Down (2 defenders in A & B gaps), or 5 Down (3 defenders in A & B gaps)," says Wimmers.  "The QB IDs the Point with the defender's number ("51's the Point!")."

Some coaches like Thom McDaniels at Glen Oak High School (OH) ties the front into their cadence.  "Our Center will make an Over (4-3), Under (Shade), Odd (3-4), or Even (4-4) call to identify the front," says McDaniels.  "Our QB identifies the coverage in his cadence.  For example: Red 4, Red 4, Set, Hut declares the coverage as Cover 4; Blue 1, Blue 1, Set, Hut declares the coverage as Cover 1. The color is not significant to the front or coverage. Our OG's will then make a Tim (inside) or Tom (on or outside) call to identify the location of the first defender to his side."

Coach Restifo of St. Ignatius High School (OH) does the same thing.  "Our QB calls out the front, the amount of linebackers and the secondary coverage in the cadence," says Restifo.  "In other words if the defense aligns in a 4-3 Cover 2. His cadence will start with 432, 432 and then the rest of the cadence."

Front Denominations

Bryan Ross, the offensive coordinator at Siloam Springs High School (AR) makes five denominations when identifying the front.  "The Center makes the call based on what he has in front of him," says Ross.  "If he is uncovered with a head up backer is middle (4-3), uncovered with no head up backer is even (4-2), covered with no head up backer is odd (3-4), and covered with head up backer is bulldog (3-3 Stack). Guards and tackles call what technique they have with each other. QB and receivers are responsible for identifying coverage on their own. QB and slot receivers are responsible for handling a blitz off the edge ("hammer"). - Bryan Ross, Siloam Springs High School

Other Examples from Survey:

From Coach Learman:

Odd = one on the center no one on the guards

Even both guard covered and no one on the center

Strong = Center and Strong Guard covered

Weak = Center and Weak Guard Covered

Eagle = Center and Both Guards covered

1 = 1 MLB

2 = 2 MLB i.e. 2 inside backers

Drew Gibbs, Ramapo High School  (NJ)

Even = Centered Uncovered no LB over him

Ace = Center Uncovered LB in his cylinder

Okie =Center Covered, Guards Uncovered

Center Calls Okie Guard can answer "Eagle" if he is covered

Bear=Center Covered both Guards Covered

Mark Melnitsky, Trinity College

Center will identify the front as one of the following:

"30" (Both Guards uncovered w/ 2 LB's in the box)

"Split" (Even front with 2 LB's in the box)

"Middle" (Even front with a middle LB)

"30 Stack" (Both Guards uncovered w/ a middle LB)

"Double Eagle" (Both Guards and the Center are covered)


Case 2:  Identifying Second Level Players

This second part of our report focuses on identifying second level defenders such as linebackers and drop safeties.  These players are not only vital in the run game, but also just as important when tied into protection.  Some interesting notes from our survey are below.  Please note all percentages are based on majority. 

  • 71.0 percent of coaches identify linebackers as names such as Mike, Sam and Will
  • 36.0 percent of coaches only identify outside linebackers and drop safeties if they are two yards or less from the Defensive End.
  • Many use game plan identifiers based on how they will line up to various formations both wide and compressed.

All of this information ties into what is commonly referred to as the "tackle box." While we have conducted research on the tackle box before (Insiders click here to view Coach Nichols complete article)  we’ve found that the tackle box is a constantly changing variable due to an offense’s ability to either spread or shrink the field based on formations.   So when we conducted research this time around we were more specific with our questions.  Our findings are below:

  • 40.8 percent of coaches call the "tackle box" the area from the Tackle to Tight End (or opposite Tackle).

Question 8

  • 36.4 percent of coaches use a number system to identify the tackle box (41, 42 etc.)- mainly in open sets.

Question 9


What we’ve found is coaches are becoming less concerned with the tangibility of the tackle box and instead relying on if defenders can be factors in the play call.   These defenders, particularly edge players are usually in a position to be influenced by run or pass action and have a dual responsibility (run and pass) once the play develops.   "We do not use yards," said Coach Lytle from Euclid High School (OH).  We just say if the defender is in position to help in the run game he is in the box."  Coach Wimmers abides by the same philosophy.  "We seldom talk about the box," said Wimmers.  "We ID threats as any non-down player who is in position to blitz or can make a tackle at the LOS and must be blocked."  Coach Nelson of Roosevelt High School (SD) echoes the same methodology.  "We focus on how do they play the run?" he says.  "Are they quickly in their gap, or slow to fill?

However there are some coaches like Coach Weakland of Sioux City East High School (IA) who include the box defenders in their count system.  "We are an inside/outside/gap team that runs Spread no-huddle who goes as fast as we can," says Weakland.  "We have gotten away from calling things 4-3 or under, or stack. We ID simply by the number in the box and 1 or 2 high safeties. We call defenses 4-0 (yes teams give us 4 in the box), 4-1, 4-2, 3-2, 3-3. We don't see 4-3 or 5-2. It's made it simpler for our OL. We don't ID Mikes, we ID play side inside linebackers or first linebackers in the box play side and count back from there. We block Defenders by their gap alignments. For example, in inside zone, play side Tackle has C Gap, play side Guard has B game. We do the same things with our protections. Everybody is responsible for their calls (Me You to 48)."

James Vint at Cornado High School (TX) uses what he calls the six-second of focus, which is something he requires his QB to do pre-snap on every play.   The responsibilities of each player are below:

Center: Front- Odd or Even, identify and communicate the Mike

QB: Middle Open or Closed

Depth-Eyes-Leverage of Corners

Finds the inverts

Communicate the Q

Checks Play if needed

Begins Snap Count



Case 3:  Identifying Secondary and Coverage

Our last component of research was focused around the identification of secondary and coverage rotation.  Before we address numbers we wanted to give credence to what has become a more holistic approach to recognizing coverage- the R4 system devised by National Football Academy’s Dub Maddox and Darin Slack.  X&O Labs released several components of the system in a prior report (Insiders click here to view Coach Maddox's complete article).  This system is geared around the identification of "tubes" on the field and where defenders are in relation to what Maddox calls the "hard deck" an imaginary line between 5-7 yards from the line of scrimmage.  While understanding the language could be a barrier at first, we’ve found a good number of those surveyed have adapted their offense to this system.


The majority of coaches, 45.6 percent, use a number system to identify coverage, more so than MFO (Middle Field Open) or MFC (Middle Field Closed) concepts.

Pre-Snap Identifiers

  • 48.8 percent of coaches feel the number and depth of safeties is the most successful pre-snap identifier for QB’s. Corners can cheat, safeties don’t lie.

Question 16

  • 49.0 percent of coaches use Safeties pre-snap vertical leverage as the number one identifier for their QB’s.  They found it was more important than horizontal leverage.

Question 19



Examples of QB’s Pre-Snap Recognition (Concept Structure)

" We read the triangle of OLB, CB & FS (width of FS & depth of CB)- Jeff Craig, Blanchard High School (OK)


"Once we determine that it is one high safety or two high safeties then the key that tips the coverage the most is keying the slot defenders. They are going to show you whether they are in man or zone because they are run force guys and will tip it with feet, eyes and alignment when they are in zone,"-  Keith Simons, Analy High School (CA)

"Our QB looks pre-snap for the safety(s) and their depth. Secondly, he checks the weak side linebacker (Will) to see if the safety is sneaking up or over to allow him to blitz the QB from the backside. A strong side blitz will usually be tipped by the depth of that Strong Safety."- Coach Hopkins, Basehor-Linwood High School

"He checks the number of defenders above the hard deck then he checks the technique and angle of the corners. If need be he checks the leverage and technique of the linebackers but that will happen last."-  Coach Gonzales, Onate High School (NM)

"We start with alignment of boundary Corner then to near Safety, then field Safety. If boundary pressed and inside we try to find if it is man press or Corner blitz? The Safeties alignment on hash or outside gives the answer. If Safety is inside hash it is Cover One or a field blitz.  If Safety is outside it is Tampa 2 or Corner fire (blitz)," Coach Marty Fine, Bryant University

We’ve found that many coaches use acronyms to teach their QB’s to identify coverage’s:


D.E.L. System- Coach Herring, Colbert Heights High School (AL)

"I always teach my QBs to read from left to right and back down to the LBs and DL. They should always read the 'DEL" (Depth, Eyes, Leverage) of the corners, and the number and alignment of safeties. Their eyes should then flash down to the LBs (number of, alignment, etc.) and the DL (techniques). This should all be done in a matter of seconds. This is something I have to constantly train and reinforce in my QBs."

(What’s the…)D.E.A.L.- Coach Nichols, Bethel College

D = Depth

E = Eyes

A = Alignment

L = Leverage

S.H.A.P.E. System- Coach Scott Meuller, Washington University

The S.H.A.P.E. principle is designed to focus the decision making process of the quarterback on every play.

SIGHT: Pre-Snap Defensive Alignment: How are the safeties aligned? Is access to the middle of the field open or closed (MFO/MFC)? The safeties are usually tied into area reads in the passing game or determine a force/run defender in the run game. How are the corners aligned? What are the depth, eyes, and leverage of the corners (D.E.L.) ? How is the under coverage aligned? Is a #2 rec. covered down? Are there pre-snap alley players?

HOT: Blitz: If the call is a pass, how does the blitz effect the protection? Progression? If it is a run, how does the pressure affect the run play?

ALERT: Automatic: Must be a "gimme" based on Sight and/or Hot.  By definition, a one vs. one winnable matchup 100% of the time. Normally live if down and distance allows: 1st down, 2nd down, 3rd & < 4.

PROGRESSION: Post-Snap Defensive Movement/Rec. Routes: QB’s post-snap progression based on the routes and what the area read and keys dictate. All coverage is tied into the safeties. We initially start with identifying what the call side safety does and work to our keys: usually OLB/S and CB to know where to go with the football.

EXECUTION: Delivering: Fake or Strike Point: QB’s fake in the run game, or in the passing game-correct drop, mechanics, and hitting the correct target based on the progression.


Examples of QB’s Pre-Snap Recognition (Numbers Structure)

Coach Bisson, Heritage High School

  1. 1st - look for the Safeties - Single High (Middle Closed), 2 High (middle open) or Zero High(Man blitz)
  2. 2nd - alignment of the corners - Single high safety with Corners off - Cover 3
    1. Single High safety with corners pressed and inside - Man free
    2. Single High safety with corners pressed and outside - Bail
    3. 2 High with corners off - Quarters
    4. 2 High with corners pressed and inside - 2 man
    5. 2 High with corners within 5 yards and outside - Cover 2



Dale Sprague, Alleghany High School (VA)

  1. How MANY SAFETIES (1 high, 2 High, 0 High) and their depth and width
    1. **Note - It is HARD for a QB to judge depth at times - easier to judge width! It takes a lot of 7-on-7 work, skellies, & reps to get it down pat!
  2. Number of defenders in the box
  3. ILBs depth and attitude (i.e. are they juking to the LOS or aligned at 2-3 yards and threatening blitz?)
  4. Corner vertical and horizontal alignment and EYE POSITION (i.e. eyes on QB is a ZONE indicator, eyes on WR is a MAN indicator).-  Dale Sprague, Alleghany High School (VA)


Bill Mountjoy, 40-year coaching veteran

  1. Scan the formation for uncovered receivers. If uncovered receivers – signal uncovered check.
  2. Find the Weak Safety for PRE-SNAP read.
    1. If the W/S is low – check other coverage keys for "Cover 0".
    2. If the W/S is high – check other coverage keys for "Cover 1" or "Cover 3"
    3. If there are 2 safeties and they are both low – check other coverage keys for "Cover 0".
  3. If there are 2 safeties and they are both high – check other coverage keys for "Cover 2", "Cover 2/Man", or "Cover 4" (1/4’s).
  4. If there are 2 safeties and they are staggered – check other coverage keys for "Cover 1/Robber" or "Cover 3/Robber".

Mountjoy does include a plan for pressure from a well-disguised secondary.  His progression is below:

A) If there is 1 safety and he rolls down hard after the snap – HAVE A PLAN VS. PRESSURE!

B) If there are 2 safeties and both roll down hard after the snap – HAVE A PLAN VS. PRESSURE!

C) If the W/S or 2 safeties maintain their alignment after the snap – execute your progression reads with an awareness of where the weaknesses are in the coverage and which coverage defender we are attacking.




As in any research project, the goal of our concluding evidence is to present you with various ideas that you can incorporate into your program.  This collection of data could be streamlined into a system that you believe in and can incorporate as soon as this Fall. We’re always in the market for new research ideas so please feel free to contact us with any you may have.




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