Teams run empty backfields to isolate WRs and open the middle of the field. With more teams opting for athletic QBs, empty sets have become a way to expand the QB running game. Defensive coordinators that want to keep a six-man box are forced to run “Zero” coverage behind the front with help only coming by late support underneath from the inside linebackers (better to just send a six-man pressure and force an errant throw), or spin to single-high. Either way, “Zero” or single-high coverage, the defense is putting its defenders in one-on-one situations. Split field defense can adjust to any empty set, but it puts the ILBs in conflict. Following base Trips rules and running an Under Front versus Empty, the Will LB is responsible for the “A” gap yet has to cover down to the weak slot. This conflict can be used against the defense and is a primary example of why Empty sets are so hard to defend.
The sister formation to Empty is Quads. This set stresses the defense even more and forces the backside safety to become a box player. The Quads set shifts the defense to the four WR side. This shift puts the DS into primary fit support in the “A” gap and completely takes the Mike LB out of the fit (another reason teams like Quads). By taking a box LB out of his fit, the offense has now forced the defense into an uncomfortable situation. Spread teams also like Quads when they have a stud WR. By alignment alone, Quads forces a one-on-one situation to the single WR side. The DS still can help the backside CB, but with any run action by the QB, or a pulling Guard, the DS must honor his fit and work into the box. This allows a brief window in the middle of the field (high percentage throw). Whether 3×2 or 4×1, the offense can put immense pressure on defenses by eliminating the RB from the backfield. All is not lost, 4-2-5/4-3 split field defenses have several ways they can combat empty backfield formations without blitzing or dropping eight.
With both ILBs removed from the box, the middle of the formation is left wide open. As more offenses turn to running QBs to gain extra yards, the defense has to find ways to combat a five-man front with just four direct defenders. For the most part, offenses use Empty on obvious passing downs because it allows the offense to have five WRs able to go vertical. This fact alone is why the best base coverage for split field quarters teams is to run Stress. Cloud to the boundary helps defenses defend the short side of the field where offenses tend to run switch routes or quick hitting out routes. The key to defending Empty is to treat it like a 3×1 set where the RB is set to the single WR side. The only difference being the RB is out of the box in Empty and a direct vertical threat.
Stress coverage allows the defense to defend the three WR side without kicking the boundary safety over to take the vertical of #3. Most offenses are not going to run a five-man vertical route, and if they do, the objective of Stress is to force the hardest throws, deep and outside. Playing split field coverage allows the defense to be plus-one in coverage and still contain the box. To the field (Stress) the defense has four over three and to the boundary (Cloud) the defense still outnumbers the offense three to two. The only difference from 10 personnel Stress and Empty are the assignments of the ILBs.
In a 3×1 set, there is still a true Mike LB (someone is holding down the box). In Empty, the box is vacated. In fact, the offense has the advantage of five offensive linemen on four defensive linemen. Versus the pass, the soft middle must be combated by the ILBs (Mike and Will) carrying any under route. In 3×1 there is a LB in the middle of the formation covering the low hole, but in Empty both LBs have vacated the box. Mike’s responsibility never changes, he must push with the #3 WR. Offenses can play on zone rules by running the #3 WR on a flat route (or bubble) to force the Mike to push. In base zone coverage, if the #2 WR to the weak side went under the Will would collision and release looking for someone coming back out. The offense can also run a Smash route to the boundary (stop/corner) to distract push the Will and run an under route from the field. If the ILBs don’t know they are defending Empty, they Mike may not carry the under and the offense is off to the races. The issue in Empty is, as stated earlier, there is no middle box player. In order to be sound, the ILBs now have to carry the under routes across the field and literally, deliver the WR to the other ILB (or until they see a WR crossing their face – Mesh).
Using Four to take on Five
Offenses use one of two ways to pass-protect Empty, big-on-big (BOB) or slide protection. Each one can be taken advantage of with just the four defensive linemen. One objective for coaches concerned with running man coverage when defending Empty has to be to occupy the OL and put pressure on the QB without sending the house. Using post-snap line movement can freeze the OL or even make them chase defenders.
One easy movement is “Tam,” or Tackle to “A” gap. This stunt is great against BOB protection. In BOB protection, the Center clamps on the Nose with the Guard while peeking to make sure a LB isn’t crashing into the “A” gap. The Tam stunt uses the BOB protection against the offense. Knowing the Center is going to clamp on the Nose to allow the Guard to overtake, there is a brief opening for the Tackle to jet into the “A” gap untouched. Even if the Guard responsible for the Tackle is able to react and push the Tackle away from the QB, the stunt has done its job. The QB most likely will run to his right (and into the DE) or step to his left and up into what looks to be a “B” gap. The key is the Will LB and his ability to fold into the “B” gap if the QB takes off. By running Cloud to the boundary the defense has allowed for Will to hang in the curl and be patient. Versus teams that have running QBs, changing the “B” gap is crucial. Head on pressure is also disruptive to timing.
The Double Tex stunt is a great “catch-all” stunt. It is good against BOB protection because it forces the OL to communicate post-snap and the stunt is also good against slide protection. Versus slide protection one of the DL will come free that is working to the outside. The slide protection and the wrapping DL will give the illusion of a soft edge and might force the QB to step to the open side only to be met by a wrapping D-lineman. Another reason the Double Tex is great against Empty is because it makes the QB feel safe when stepping up on a Draw play. The objective here is to make the center of the formation look soft, only to get the QB hammered if he steps up on a draw by the wrapping D-linemen.
Another stunt built off of full line movement is the single DL wrap. If the offense uses slide protection and slides to the Tackle’s side, the defense can use full line movement and have the Tackle take a step up and wrap back to the open side (all while the front side DE and Nose work to the boundary). This movement, like the Double Tex, gives the illusion of a soft edge (this time to the field). DCs that run this stunt must have an athletic three-technique that can make it to the edge in time (that’s a long way to go from boundary “B” to opposite “C”).
A Quads formation is similar to an Unbalanced one. Simply put, there is a player where he should not be. In the case of Quads, the #2 weak slot is now on the three WR side. This forces the defense to shift to the Quads side and exposes several areas of the defense. First, the “A” gap is exposed. Using cover down rules, the Will must honor the #2 weak player and relate to him. This puts him in a “hip” alignment on the field DE. Second, the formation puts the boundary safety in primary support (he is now a box player – “A” gap defender). Most DCs would not want their DS as their Mike LB, but in split field coverage, there is no choice.
Spread teams like the 4×1 set if they have a stud WR because they know they can truly force a one-on-one situation. The key to defending Quads is the backside safety (DS). His role is to hold down the middle of the field and attach the QB draw. The CB must be aware that he has very little help and only to the inside. Keeping with structure rules, the defense still has plus numbers, it just looks awkward. If the defense spins to single-high the box is filled, but the CB truly is on an island. In order to help the CB out and rally to a QB draw, the defense can shift over to the Quads and put the DS in primary support. It may not be ideal, but it forces the offense to think about throwing to the Quads side and the DS, depending on down and distance, can rob the backside WR.
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