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Decoding Langsdorf: Nebraska’s Gap Duo Blocking Scheme

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The Huskers staple run is one of popularity, simplicity and power.

David McGee

The cowboy poet Rudy Linstrom once said, “Texas is a desolate place. Dry, windy, hot and flat. It creates tough people. People who endure extremes. Only other place that comes to mind with tougher conditions, tougher people, and the requirement of greater resolve might be Nebraska.”

Because of the rugged nature of Nebraska as so eloquently stated by Rudy Linstrom, the good people of the state of Nebraska have always identified with the rugged nature of the running game, whether the running game be comprised of fullback traps, option quarterbacks, or homerun hitting I-Backs.

In fact, one could almost imagine that the great Nebraskan William Jennings Bryan would have stood at a pulpit, extolling and vigorously defending the virtues of displacing the line of scrimmage. From the pulpit, adjectives such as nasty, hard-nosed, and resolute would have flowed forth in an impassioned promotion of the running game.

Today, we will take a look at a nasty, hard-nosed, and resolute run play that Nebraska displayed on consecutive plays in April’s spring game. This play is known as Gap-Duo, or as offensive line coach Mike Cavanaugh referred to play, “power without a puller,” at the 2016 Nebraska coaches clinic.

Although Cav mentioned this play before last season, I had very little insight on the play (read: none). Because of my discovery of this play over the winter and spring, I’m now curious about how many times NU ran Gap-Duo last season while I steadfastly believed that I was watching an Inside Zone play unfold. Additionally, head coach Mike Riley referenced this play to reporters during spring ball when described the need for identity runs.

Gap-Duo is a downhill run play that is predicated upon vertically displacing the defensive linemen with as many double team blocks as the defensive alignment will allow. Moreover, Gap-Duo looks nearly identical to the Huskers’ bread and butter run concept, Inside Zone, although with a few semantical differences. Starting from the pre-snap to post-snap, the semantical differences begin with who the center ID’s pre-snap.

On Inside Zone, the center will ID the MIKE and zone playsidetoward the MIKE, working with the playside guard against a 1 or 3 technique defensive tackle. On Gap-Duo, the center will ID the WILL to the weakside of the formation, the direction in which the double team blocks will rotate toward. In this case, if the tight end is aligned on the right side of the formation, the WILL is on the offense’s left and the entire offensive line will work to their left in order to secure the first level of the defense and rotate the double team block to the linebacker.

Another semantical difference is the read of the tailback on the play. On Inside Zone, the tailback is reading the first down defensive linemen (DLM) playside from the center, although a shaded nose guard would not count, which typically leaves a 3 technique DT as the tailback’s read. On Gap-Duo, the tailback has a binary read of the MIKE. If the MIKE scrapes, or widens, over the top to the outside, the tailback will take the ball on a vertical path into the playside B gap between the guard and tackle. If the MIKE decides to thump downhill into the B gap, the tailback will bounce the ball to the outside. Even if the MIKE doesn’t get blocked, the tailback can return the favor to the offensive line and still make them look good by making the MIKE wrong and generating positive yardage.

1st&10 2nd Quarter 8:43

On this play QB Patrick O’Brien led the Red squad down the field into scoring position on the White 25 yard line. On first down, the Red squad aligned in an off-set I “Near” formation with Devine Ozigbo at tailback and Luke McNitt at fullback. Last season, this formation was synonymous with outside run plays with McNitt plowing the road for the tailback on the perimeter. However, this time the Z receiver, Gabe Rahn, motions in toward the formation, an obvious sign that Rahn is looking to seal the force defender and force the cornerback to crack-replace and become the force player himself on the perimeter. This is a bad predicament for most cornerbacks, as most CB’s aren’t fond of tackling in run support. In this case, DiCaprio Bootle would be the force defender to the outside if Devine Ozigbo were to bounce the play wide. At the snap of the ball you can see Rahn move vertically to block either the safety, thus leaving Bootle alone on the perimeter.

Cole Conrad, auditioning at center this spring, ID’s #31 Greg Simmons as the WILL and the offensive line doubles the interior DLM’s in that direction. On Gap-Duo the blocking rules stipulate that basically everyone except the backside offensive tackle has a primary responsibility of blocking their interior gap. On the backside of Gap-Duo the backside offensive tackle will fan block the defensive end to the outside. Against an Under front, the backside offensive guard will also fan against a weak side 3 technique.

On this play, Boe Wilson does not have an interior gap threat, so he is doubling on the loosely aligned 3 technique with David Knevel, while Cole Conrad and Jerald Foster double the 1 technique. Because Wilson does not have an interior threat, he is the post man on the double team block, cutting off an inside slant and effectively setting up the 3 tech to be taken over by Knevel.

Once the 3 tech is set up for Knevel, Wilson climbs to the second level. Wilson does a phenomenal job of cutting off any inside slant, securing the first level, and climbing, but not chasing, Greg Simmons in the second level. Wilson also showed one of the best attributes in an offensive linemen: he keeps his feet moving through contact. Keeping your feet moving through contact is the key to sustaining and finishing a block.

Remember earlier when I mentioned that the tailback’s read is the MIKE and that the tailback takes the ball opposite of where the MIKE goes? Well on this play, the MIKE, Avery Roberts, is influenced by Luke McNitt’s wide block and scrapes over the top into his outside run fit. Seeing this, Ozigbo takes the ball on a vertical path, although cutting back to the A gap inside of the playside double team due to the B gap being clogged by the double.

Against other alignments, such as the 4-3 Over with the SAM tucked inside of the 9 technique defensive end, McNitt will likely insert into the C gap. In this 4-2-5 Over alignment, the “SAM”, Tyrin Ferguson is aligned very wide to the field, thus necessitating McNitt’s wide block.

1st&10 2nd Quarter 8:03

Immediately after the first down run by Devine Ozigbo on Gap-Duo, the Red squad comes out in a bunch formation with Jack Stoll, Tyler Hoppes, and Demornay Pierson-El comprising the bunch aligned to the field. Because bunch categorizes as a trips formation, the defense aligns in an Under front in order to adequately cancel out gaps by alignment and to better allow the linebackers to fit both into their run responsibilities and pass responsibilities more easily. The Under front calls for the 3 technique to align on the weak side of the offensive formation rather than the strong side. Rather, the 1 technique will align strong, this time on the right shoulder of Cole Conrad.

On paper, Boe Wilson technically should be the drive man and Conrad should be the post man on the double team block. However, on this play #75 Joel Lopez immediately engages Conrad, leaving Wilson to chip him away from the B gap point of attack on the play with the forearm flipper blocking technique. Now that Conrad and Lopez are fully engaged, Wilson is free to climb to the second level, where he again finds Greg Simmons. Again, Wilson displays fantastic technique, as he hand-fights for inside leverage against Simmons and does not stop moving his feet. Wilson’s block was the penultimate block that sprung Ozigbo for the touchdown.

Elsewhere on the play, David Knevel and Jack Stoll double team the 5 technique defensive end, with Stoll coming off of the double to block a scraping Avery Roberts. The great thing about Gap-Duo is that the more blockers you align to the strength of the formation, the more double teams you’ll get on the down defenders. On the backside of the play, you’ll see that Foster and Gates are fanning the 3 and 5 techniques.

Although Luke McNitt is not present on the play, Avery Roberts again reads outside run and fits into his outside run fit. This is by the offense’s design. Although the 4-2-5 defense Diaco employed in the spring game is semantically different than the 3-4 we will see this fall, many of the concepts remain the same.

In most 4-2-5 defenses, the MIKE is coached to read the fullback as his key against two back formations and to read the tailback in one back formations. You’ll notice that Ozigbo’slead step opens like it’s an outside run play, only to square back up to the line of scrimmage just before the hand-off. In my own estimation, both the wide block by McNitt and the wide lead step by Ozigbo are by design, to the influence the linebackers into making the wrong read.

Gap-Duo was just one of the “new” run schemes shown in the spring game. In the next edition of Decoding Langsdorf, we’ll take a look at the Counter Trap that the Huskers ran in the spring game. GBR!