One of the hardest sets in football to defend is the cluster or stack set. Spread offenses utilize this set to get the defense’s outside linebackers in run/pass conflicts. Unlike a traditional 2×2 set, the defense has to adjust to the width of the receivers. Stacking them creates width, and width creates the conflict. Spread teams rely on the open “B” gap to build their RPO’s and offensive gameplan. By stacking the receivers out wide, the defense is forced to adjust. In a two-high system, the player in conflict (usually the Will LB) has to choose, cover down to his receiver or hold tight to the box. If he stays close to the box, the offense is going to throw the quick screen and create a 1-on-1 open field tackling matchup with the safety or corner. In most cases, the defense wants to avoid this as much as possible. On the other end of the spectrum, if the defender widens to the cluster set, the offense has a 4-1 box and a clear running opportunity. Versus a two-high system, there is a great chance for the offense to part the field like the Red Sea for a big gain. Ask any offensive coach, a 4-1 box is a magical thing.
In the image below, Penn St. runs and Under front and “hips” it’s Sam LB to the strength. In most RPO style offenses, this is a clear pass read. The Sam has to honor the run read and step to his gap. Even with zone away and a gap exchange with the crashing DE (in this set the DE has dive), the Sam has to take a step towards the box. The QB is taught to read the Sam’s path and throw the screen. Penn. St. is most likely in a “Cloud” coverage (Two Read) and the safety is bailing on the snap. Easy pickings for any decent offensive coordinator. It’s a conflict of philosophy; the offense wants 1-on-1 matchups and the defense wants a plus-one. In order to create a six-man box and protect against the run, the defense has to spin to single-high, but to keep a plus-one in pass distribution it has to stay in two-high, something has to give. MatchQuarters explores the options.
Different Trains of Thought
4-3 Over Front
In a traditional Over front, the defense has a fold player to the weak side. Most 4-3/4-2-5 hybrid defenses, when facing 2×2 spread, will either set the front (the 3 technique) to the back or the field. By setting the 3 tech. to the back, the defense is forcing the offense to hand the ball off on any read play. The defense can use this to its advantage against RPO teams, and force the offense to put the back into the boundary. Clever offensive coordinators will flip the read. If the offense sets the back to the boundary, and the defense sets its strength to the back, the Will is still in conflict. The offense can flip the read and throw the RPO if he folds into the “B” gap. Add a stack set, and the Will is far removed from the receivers, leaving the safety and CB in 1-on-1 matchups.
The best answer for a cluster set in a 4-3 is to check to a “Cloud” coverage or Two Read. When offenses stack receivers they are most likely going to run some kind of a high-low concept or horizontal stretch. Even if both WRs go vertical, the Cloud concept allows the CB and safety to absorb the verticals. The offense is not going to run both WRs vertical one after another, the WRs are going to deviate at some point. The Cloud coverage scheme plays into this because it is essentially a high-low defensive scheme. Along with the coverage piece, the Cloud concept enables the Will to hang in the curl and be slow to fold. Even if the receivers run a screen, the Will is responsible for the curl and can literally sit. Most RPO teams are reading the OLB. In Cloud, the stagnant OLB can create hesitation. As all DCs understand, hesitation in an RPO scheme creates turnovers and bad reads.
By running an Over front the defense is ensuring a handoff by the QB and/or keeping the read player to the boundary. In the middle of the field (MOF) the Will is in more conflict, but running a Cloud concept can keep him in the curl long enough to hold the read of the QB. Essentially, most teams are going to run zone. This allows the Will to fold in late because the RB is most likely going to cut back anyway. The Sam is apexed even though in a traditional set he would be covered down. Cluster sets can also be used as a leverage tool for the offense. If the Sam widens too much the defense is exposed to speed option. By apexing the Sam, the defense can hold the curl and the Sam’s position, allowing him to attack downhill on ball handed off.
Offenses that run cluster sets read the box for run or pass (hence RPO), it is the DC’s choice as to what is his biggest concern. If the offense has a great running game and the DC wants to load the box, single-high might be the way to go. Against heavy run spread teams, especially RPO teams that are heavy run, it might be to the defense’s advantage to load the box. The only way to achieve this is to spin to single-high and gain a hard six-man box. Inserting the Will can plug every gap and give the defense a plus-one versus the run. The only question the DC has to ask now is, who he wants to run the ball? As stated earlier in the piece, most four-down teams run an Over front and set the 3 tech. to the back. This creates a handoff read for the QB because the strong-side defensive end is the QB player.
Where the defense is stressed is in the pass. Stack sets versus a single-high eliminate the deep safety from the play by alignment, essentially letting the offense gain an extra man. Versus an even set (2×2) the single-high safety will lean on the running back, or shade to the best receiver’s side. This alignment tweak can expose the defense. If the offense play-actions and throws four verticals, the centerfield safety has to read the QB and break on the ball thrown. In the picture above, the defense is pressing the “on the ball” receiver. The Cover 3 in the secondary is much like an inverted Cover 2. The OLB and spin safety are responsible for the underneath, while the CBs are responsible for the deep routes. In most RPO offenses, a six-man box tells the QB to throw the ball. By pressing the curl players, the defense is forcing the issue right now, though leaving themselves exposed to the fade/slant combination.
In order to protect against the pass, a DC could choose to run a loose Cover 3 look. Much like the Two Read explained above, the Sam and safety hang in the curl and absorb anything underneath and inside. Teams that run switch screen RPO’s can have an angle on the curl player and force a 1-on-1 matchup with the CBs. The real adjustment in single-high is what to do with the curl players, loose or press. Each technique has its perks, but it really comes down to what the offense is doing. Are they a switch screen RPO team, or do they attack vertically with a fade’slant concept? Against screen teams, it may be necessary to force the issue right now, while against vertical RPO teams a DC may need to be more passive on the edges and absorb the routes. Single-high is a great adjustment if a DC knows the offense wants to run the ball and is only using the stack sets as window dressing to move his players. If a team is true RPO offense, it could be to the DC’s benefit to stay in two-high.
Much like the 2×2 stack sets, the Bunch set is used to stress the defense, but in a different way. Anytime an offense aligns in a 3×1 set, it has the opportunity to go vertical and stress the defense. Versus a two-high scheme, the defense can gain a plus-one, but it is stressed versus four verticals. Single-high is able to load the box, but the pass distribution is the same and the defense loses a defender to the single receiver side. Most offenses do not run four verticals out of bunch sets because of the spacing. Instead, many rely on high-low concepts. In order to match up, and stay sound to the boundary, a defense treats the bunch much like it does a stack set. In the diagram below, a “Cold” call is needed to tell the Sam to apex the bunch and hold the curl. The Mike is allowed to stay in the box and hold the run. The CB is responsible for the first outside route, while the Sam is responsible for the first “in” route. The safety holds leverage over the bunch and protects the vertical. To the boundary, the safety and CB stay in quarters coverage allowing the safety to “rob” the curl and attack the run game weak. If spinning, it is best to press the Sam, and have the spinning safety hold the curl. The CB, who is outside the bunch set needs to work over the unit and hold any vertical. If the offense aligns the Bunch set tight to the box, the Sam must align outside the “on the ball” WR and press the outside shoulder. The CB aligns 3×3 off the outside man, holding the edge if there is an outside run play. Teams use the bunch to gain an advantage in the run game, especially is aligned to the box.
Attacking Stack Sets
The Double Ted stunt is a great way to use four defensive linemen to create plus numbers in the box. Versus a zone team, the end to the play should be able to loop back inside and add to the box numbers. It’s a way to gain a six-man box without spinning. Both ends take a step upfield and then fold back into the box, mainly aiming for the “A” gaps. The Tackle and Nose hold the “B” gaps like anchors. In theory, the Center will climb to the Mike, and the play side DE will run untouched in the “A” gap to make the tackle (see video below). The coverage in the diagram is a Cover 2 scheme to enable the OLBs to hold the curl and attack the “C” gaps. In the video below, current Michigan DC Don Brown, and former DC for Boston College uses this stunt to combat Florida St.’s zone RPO. Even though the play side end misses the tackle (runs right by the back), anyone can clearly see this is a great stunt to combat the stack set RPO. Since the defense is not blitzing a man, the secondary can run any base two-high scheme or spin depending on the DC’s preference. Don Brown in the video uses a hybrid trap-two concept to allow the weak nickel to fill the “C” gap quickly against the run.
Change the Read
The biggest factor when facing any zone read team is who does the defense want to carry the ball. If the QB is a run threat, the defense is better off playing an Over front and forcing the QB to hand the ball off, but if the DC would rather the QB run it, change the read. Changing the read can be done several ways, mainly changing the line post-snap. Anytime a defense changes the “B” gap it gives read offenses trouble. Against run heavy spread teams a defense can spin to single-high with success. In the diagram below, the defense uses line movement to change the read of the QB. Just by moving one player, the defense can create a scheme that counteracts the RPO read of the QB. By inserting the Tackle into the “A” gap the Mike is able to “rock” to the field. If the QB decides to throw the RPO, the Mike is already moving that way and makes his job of cutting off the inside much easier. Just like in any 4-3, DL/LB exchanges are key when defending the zone read. The “Tam” makes the DE take the dive, allowing the Mike to attack the “C” gap. The field CB is playing a “robber” technique while the Sam is pressing the WR on the ball. This stunt can also be utilized in a two-high scheme.
Spread sets are designed to stress the defense and make the DC show his cards early. The width of the WRs makes it difficult for any defense to get the cover down they want. It is important to always understand why offenses are using these sets. Many times, offenses use the stack sets to widen the defense out to get a favorable box, or force the defense to spin leaving them vulnerable to the pass. Defending stack sets with a Cloud concept plays to the law of averages. In a stack or bunch set, the offense is most likely to run a high-low scheme or a screen. Two-high or single-high really relies on what the offense is trying to do. If the offense is heavy run, and using the stack sets to attack the 4-1 box, then spinning might be the answer. If playing an RPO heavy team that likes to pass out of the cluster sets, then a two-high Cover 2 scheme keeps the defense safe.
There is no reason why a defense cannot attack stack sets. Offenses use stack sets to force DC’s to check out of a blitz. Using zone blitz principles and schemes can alleviate some of the issues with man blitzing stack sets. Like with any spread read scheme, the best way to defend against it is to change the “B” gaps with line movement. Change the cover downs to confuse the QB by spinning or moving the line. Don’t “Omaha” a cluster set, use good defensive principles, zone concepts, and line movement to attack the spread at its own game.