clock menu more-arrow no yes mobile

Filed under:

2015 Clemson Football Season Preview: Defensive X's and O's

Almost. There. With less than a week to go, let's open up the playbook and talk scheme and strategy.

Who's ready for the Shaq Attack?
Who's ready for the Shaq Attack?
Robert Mayer-USA TODAY Sports


Let's get started with some good news!  From what I saw in the spring game, if we have a top 25 defense then our offense is National Championship level without Watson.   Of course, that is most likely not the case, but then again, it IS possible.

In all likelihood though, the defense was out-experienced and over-matched in the spring game by an offense that is probably more like top 45 without Watson.  Considering the fact that we will face seven Top 45 Offenses from last year, we could be in a lot of shootouts.

The Orange and White defenses that afternoon gave up 52 points combined in the first half and gave up big plays in both the run and passing game.  The Orange defense gave up 7.7 "yards per play" which, to put that in perspective, is the same "yards per play" that Jameis Winston and Florida State put up against us in 2013.

Since the spring game, we have lost Ebo, Korie Rogers, Korrin Wiggins, and D.J. Reader.  The coaches have stopped touting the defense so much in the press like they did the first week or two of fall camp.  With so many unknowns, and yet so many great athletes, it's hard to pin down how effective the defense can be this year.

A large contributor to that effectiveness remains that the offense and defense are married.  After a year off, Dabo is suggesting a return to the racecar HUNH we ran from 2011-2013. With some of the best offensive talent in the nation on our roster, I'm in favor of a racecar HUNH this year and prepared to accept a defense that gives up more big plays and has more mental busts. However, schematically, I expect Venables to put more speed on the field this year in order to mimic the havoc that was created routinely by last year's #1 defense.

In the Korrin Wiggins injury article I posted that if they didn't move anybody over to NB/SAM, "This means that they are comfortable with the Blanks/O'Daniel Combo and, while we will miss Wiggins' versatility, these two have proven to the coaches that they are capable." Well that's what happened, which is a good segue to schematics because how we choose to defend relies so much on the skill set of the Nickel/Sam.

Basics of Clemson's Scheme

We run our BASE defensive scheme primarily on run situations (like first and 10) or against 2 WR personnel.   Base consists of 4 DL, 3 LBs, and 4 DBs.

Against 3 and 4 WRs and in probable passing situations (like 2nd and 10 or 3rd and 6) we run our NICKEL package. Venables' Nickel consists of 4 DL, 2 LBs, and 5 DBs.

In certain pass situations (3rd and long), Venables employs a DIME package that gets all those speedy DBs we loaded up on a couple years ago on the field at once.  This package was devastating last year to the point to where it earned the nickname from me, "Dime of Doom."  Venables' Dime is run with 3 DL (2 DEs, 1 DT), 2 LBs (Goodson and likely Kearse), and 6 DBs (we don't know the personnel here just yet but Jadar Johnson and Adrien Baker should be two of the three we bring in).

With the proliferation of the spread formation, we will align using Nickel personnel more than any other personnel grouping.  However, against our biggest opponents (Notre Dame, Georgia Tech, Florida State, and South Carolina), we will lineup with base personnel more often.

Over /Under

In 2013, our base defense was 4-3 Over. In 2014, our base defense switched to 4-3 Under. In the spring game we ran primarily 4-3 Over.  What does this mean and why all the switching?

The reason a DC would choose an Under or Over alignment is based on the skill set of primarily the WDE and NB/Sam.  The biggest difference between Over and Under is that in Over, the Sam/NB lines up outside the DE on the TE side at LB depth.  In the Under, the Sam lines up on the line of scrimmage on the outside shoulder of the TE. In effect, the Under creates a 5 man front and blurs the line between a 4-3 and a one gap 3-4 scheme.

4-3 Over look against 21 Personnel (2 RBs and 1 TE).

So, the decision to go Over or Under is typically based on your own personnel 1st and then "style of offense" and personnel of your opponent 2nd.  The idea here is to get your best 11 guys on the field in base and then worry about adjusting to the offense as dictated by formation, situation, and offensive success against your base scheme.

In 2013, we had Quandon Christian at Sam and a shortage of capable DBs.  Christian was an experienced hybrid player that could run a 4.6 at 225 pounds.   He had the skills to cover a slot receiver like a NB, especially in zone coverage, and also the punch to play at the line of scrimmage like a LB.  He graduated after the 2013 season and left us without a true Over Sam.

So in 2014, Venables split the duties between two players.  We had Vic Beasley who was a sensational pass rusher but there was some concern about his ability to hold up against the run (see FSU 2013).  So, a 5 man front in base would give him the green light to rush off the corner and give him help against the run.

When B.J. Goodson was in the game, he would play on the line in Under and often be tasked with manhandling the opposing TE.  Wiggins would come in for Goodson in passing situations or against spread personnel, and play over the slot WR. Wiggins would rarely be in the game unless there were 3 WRs.

4-3 Under look vs. 21 Personnel (2 RBs and 1 TE)

This year, Goodson has moved to MLB and in the spring game, we saw a lot more Over.  My biggest concern with Over is at DT.  Over demands that the DTs attack and get off blocks. In Under, they can control their gap, occupy the OL, and the LBs can make the play.  I'm not sure if we have the playmakers at DT to be dominant in the box initially.

The typical way to address the lack of playmakers on the DL is to use stunts and slants to keep things aggressive in gap charge.  However, they still have to do something when they get there and I didn't see that much at all in the spring game.  Therefore, if we see Under this year, I still think that would involve Goodson moving back to Sam and Kendall Joseph taking over at MLB.   We probably won't find this out if this is necessary until we have to stop the Notre Dame rushing attack in game 4.

Even though you haven't heard a peep about this during fall camp, I still think Under with Goodson at Sam is something the coaching staff will use if needed.


When we defend the pass, we will use C2, C3, C6, and man to man, but when we do run man, it is often run behind a blitz.  We will occasionally employ robber and The most common coverage, and you might say our base coverage concept, is C4 or Quarters.  Here is a great read on Quarters here by Ian Boyd that was posted on Football Study Hall.  The diagram below also explains responsibilities as well.

Quarters is an effective "cover-all" because of its flexibility.  If the secondary (and pass rush) does their job, the offense is more likely to find an athletic mismatch then a schematic mismatch. When you have great athletes in coverage, it's hard to find an athletic mismatch.

Because we have big athletic safeties, these guys can be a factor in defending the run, blitzing, and covering in man.  It is their proficiency against the run and ability to create a matchup advantage in man to man that allows us to run C4 so effectively.

The way to beat Quarters requires the QB to have time in the pocket.  A deep fade is often going to be a 50/50 ball and a deep crosser behind the LBs can be effective if the WR can completely cross the field. Last year, it was rare that a team could do that to us because we had the best pass rush in the nation. This year, it's a different story.  With a diminished pass rush, we will be dependent on our talented secondary to cover longer and better than they did last year.


The mark of a good coach is that he can put his personnel in the best position to be successful.   This can involve situational substitution, variations of responsibilities, and stunts.

There is not enough room to breakdown, position by position, all the different variations we will see this year. Also, Dr B. has put the work in and done a fantastic job of archiving almost everything you would want to learn in our archives here at STS.

So instead, I decided to present how I believe we will most often address our strengths and weaknesses defensively. That way, when you're watching the game, you can pickup on these things and better identify the "game within the game."

We have personnel advantages at certain positions and if you've read this far, I'm sure you already know who they are.  Shaq Lawson, Jayron Kearse, MacKenzie Alexander, and perhaps now, T.J. Green, are complete players with no glaring weaknesses.

We should have a matchup advantage at these spots in almost every game we play this year.  They will be counted on to do their job and win battles consistently.  Simply put, we will scheme for them to have more responsibility more often.

You are going to see Mackenzie Alexander on an island a good bit this year and he will have every opportunity to back up that "best CB in the nation" moniker he gave himself recently.  He is going to be tested by fades and posts every game, especially by zone read teams that want to get Kearse and Green rolling back at the snap and out of the tackle box. If he can do that, our quarters coverage will work.

Our perceived problems/drop-offs from last year (at least initially) will be playmaking at DT, edge setting at SDE, downfield coverage at BCB, play diagnosis at MLB, and underneath coverage at WLB.  These will be targeted areas by opposing offensive coordinators until we can prove that they are not weaknesses.

So, if I'm an OC, the first thing I'm going to do is put strength (TE) to the short side of the field and run behind that strength a lot because I can take advantage of all these disadvantages Clemson may have at once.   There is in-game precedent for this too as this is basically what Georgia did to us in the 4th quarter last year when Crawford and Peters were out.

The ways we will most likely defend this is to drop a safety in the box, blitz the BCB, or slant the DL to strength. This will either dare the opposing offense to put the ball in the air downfield, run power/counter to the weak side, or throw to the RB weakside against Boulware.

The way we will hide Boulware against the pass everybody already knows, he will blitz a good bit.  He is a dynamic ball of butcher knives when he hits the line. It is beautiful.  He can make penetration with speed or power and then also make plays when he gets there as well.  The next thing we will do is simply get him out of the game in obvious passing situations.  Playing Jayron Kearse at WLB in the 3-2-6 Dime package is an excellent decision.

We should see a lot screens and draws this year as well and some of these are going to go for big gainers.  The trade off will be that drive ending sack, TFL, or turnover.

Stunts and Blitzes

The first thing to know about blitzing I've already mentioned.  "Good coaches put their players in the best position to be successful."  So, what we ran last year might not be the same this year.  However, broken down, these are the most common stunts/ blitzes we ran and the basic terminology that I will use in the film review.

A typical defensive playcall will signal the front, alignment, coverage, and/or stunt/blitz.  So, the combinations of all of these calls can be detailed, vary in terminology from coach to coach, and change from opponent to opponent. There may be 150+ different calls in a defensive system.

Trying to absorb this can bog you down in verbiage that means nothing to you (ie. like a Kevin Steele post-game interview).  If you make the effort here though, the basics of strategy are fairly easy to learn and will go a long way to helping you understand the beautiful chess match going on.

A "stunt" is where two players will exchange roles on defense to confuse the blocking scheme.

A "blitz" is where a player outside of the front 4 crashes the line of scrimmage.

Here are the stunts we commonly ran last year

TE stunt - (Tex or Nex) Tackle slants to the outside C gap and the defensive end loops around on the inside to the B Gap.

Twist stunt -(TT stunt) One tackle slants toward the other tackle and that tackle loops around to fill the gap he left.

Slant - (Rip/ Liz, Army/Toro) The 4 DL slant in the same direction at the snap with each moving over one gap. The LB away from the slant moves up to cover the C/D gap.


Bullet - LB penetrates the A or B gap in front of him and gap assignments stay the same for the DL. This is a "Run Blitz" as it removes a LB from coverage and makes a pile at the line of scrimmage to stonewall a running threat.  Since the playside DL is usually double-teamed initially, often the LB can penetrate past the OL before they realize what happened.  Double Bullets are when both ILBs blitz this way.  Boulware is very proficient at this style of blitz.

X blitz - (Max, Wax, Sax) An "X blitz" is often run in conjunction with other blitzes. The DL crosses the face of the OL in front of him and takes the gap on the other side from his alignment (usually inside). The LB loops around and attacks the gap the DL vacated (usually outside).  The other version of this is the opposite. The NG will loop outside and usually both LBs will crash the A gap on either side of the Center. A "Double A gap Cross Dog" is shown below.

Fire/Smoke - S/NB/LB/CB blitzes off the corner from the D gap. The aim point is usually the deepest back in the backfield.

Overload Zone blitz- the NB/CB and LB blitz on the same side creating a 4 rushers vs. 3 blockers situation. The FS has to move forward to cover the hot route on that side, the backside LB replaces the blitzing LB, and the DE on the backside drops to the seam.  This is the one where Corey Crawford picked off Aaron Murray of Georgia in 2013.

Jailbreak - 7 man blitz we run about once a game where we send the MLB, WLB, and NB/Sam. Man to man coverage is played behind it.

Well, have you figured the overall theme out yet?

Aggressiveness! Venables wants his guys coming downhill, having fun, and making plays.  Players often take the personality of their coach and you can see that Venables' "Rabid Squirrel" persona has rubbed off on the players.

The past two years, we have led the nation in tackles for loss and first down percentage (percentage of opponent's drives that do not achieve a first down).  So, I'm not saying Venables is the best defensive mind in college football or even the ACC for that matter, but I can still stand by my opinion from 2011 that he is the best DC for Clemson right now.  That's all that matters.

The Tiger Defense has been doing what a HUNH defense should do. They get off the field and get the offense back on the field as soon as possible.