Back with another round of Scheme Fitting! This time we’ll be looking at the 4-3 Under Front. I want to give a basic overview of what the defense is, what the basic concept is and what type of coverage you can run behind. Along with that we’ll look into which 2022 Draft prospects fit into this defensive scheme. Let’s go!
First off let’s define the scheme. The 4-3 Under front on tape can look very similar to a traditional 3-4 defense. But there are some differences. This front was made popular by Gus Bradley and the Seattle Seahawks in the Legion of Boom days. Other teams like to 2008 Cardinals and the Eagles in the Chip Kelly days used a 4-3 under front as well. What you have in a 4-3 Under Front is 4 down linemen, 2 stacked Linebackers and an on-ball LB, usually the SAM. Behind that you can run anything from Cover 1 to Cover 4.
The idea of this front is to get single gap penetration and 1 on 1 matchups. The keys to this 4-3 Under front is are the 3 Tech and Weakside DE (also called the LEO) as well as the versatility of the SAM LB. Your 3 Tech and LEO must win their respective 1 on 1 matchups. The scheme is designed for them to be isolated, so the burden is on them to dominate their respective matchups. As we all know if a defense can’t generate pressure the QBs in today’s NFL will pick you apart.
Let’s get Technical
You can identify a 4-3 Under front by formation. In a 4-3 Under the A gap and C gap to the strongside are always covered and the B&C gaps to the weakside are covered. The strongside of the formation can also be called the TE side or Run strength side as well. So, what you will have is a Nose Tackle lined up on the Center shaded to the strongside, a strongside DE lined up on the OT in a 5 technique, a 3 Tech lined up in the B gap of the weakside and your other DE in the C gap of the weakside. The strength of this particular alignment is that nobody but the NT can be double teamed. If you have a NT that can command a double team you guarantee a 1 on 1 matchup for your 3Tech and Weakside DE.
On the second level you have your basic MIKE, SAM and WILL Linebackers. The MIKE has strongside B gap responsibility in the run game and usually spot dropping in the pass game. The WILL has weakside A gap in the run game and plays the overhang against the pass. While the MIKE and WILL are lined up stacked 4 to 5 yards behind the line of scrimmage, the SAM is lined head up on the line of scrimmage against the TE. The SAM has multiple duties depending on the play. He is either rushing the passer, setting the edge versus the run or carrying the TE in man coverage.
Coverage can be pretty versatile behind this front. You can stay in your base defense and run some Cover 6 if the offense has trips (3 receivers one side) to one side of the field. If the offense is running some 2 by 2 sets (2 receivers on each side of the formation) still stay in base and run some Cover 4. For this exercise let’s get aggressive and play some Cover 1. Let’s disrupt that timing on offense and give our pass rush some time to attack.
Enough X’s and O’s, let’s talk about the Billy’s and the Joes’s
Defensive Line
0 Tech/Shade – As stated above the NT is shaded to the strongside in this Under front. He is the only player on the defensive line that is likely to see a double team. What is required is a player that can command this double team. While engaged this 0 shade has to be strong enough to hold his ground. Preferably a big body is necessary.
John Ridgeway NT Arkansas 6’5 327 – Ridgeway is the exact type of player required. He plays the NT and is at times shaded to one side of the Center. Ridgeway has a strong anchor against double teams and show the ability to push the pocket.
Strongside DE – This position requires a bit of play strength. The strongside DE is tasked with setting a hard edge against the run while aligned head up on the OT from a 5 technique. Strength at the point of attack and the ability to disengage and attack is key.
Josh Paschal DE Kentucky 6’3 278 – Josh Paschal has experience lining up at 5 tech, 4i and 3tech. He is no stranger to close quarters combat. Paschal shows excellent power at the POA and the explosiveness to displace offensive linemen when time to shed a block.
3 Tech – In this 4-3 Under front the 3 tech is one of the stars of the show. Tasked with attacking 1 gap and attacking a single blocker. The success of this front depends on the 3 Tech winning his individual matchup consistently.
Perrion Winfrey DT Oklahoma 6’4 292 –Perrion Winfrey wasn’t used as a gap penetrating 3 tech much while at Oklahoma, but when he was the explosiveness and pash rush ability was exceptional. When asked to attack the passer, Winfrey can be a consistent threat for any guard trying to block him.
Weak Side DE/LEO – Just like the 3 tech, the weakside DE is facing a single blocker and tasked with winning his 1 on 1 matchup to create pressure. Usually aligned with a wider split (7 or 9 tech) the weakside DE must possess the type of athletic ability to threaten with a high side rush and the change of direction ability to counter to an inside rush.
Kayvon Thibodeaux DE Oregon 6’5 258 – Thibodeaux shows high end traits when asked to attack the passer. Whether he is running the arc with a dip/rip move or a ghost rush or using a euro step to counter inside, Kayvom Thibodeaux has the traits to bring consistent pressure from the outside.
The Second Level- Stacked and On-Ball backers
Stacked LB – In a 4-3 Under front, the stacked LB are responsible for whatever gaps the defensive line isn’t covering. In this case that would be the strongside B gap for the MIKE and the weakside A gap for the WILL. Aligned 4 or 5 yards directly behind their gap assignment, these stacked backers must diagnose quickly and trigger downhill. Against the pass the MIKE is dropping back into his zone relating to any crossers, the WILL takes the flat and will possibly cover the #3 receiver in trips.
Channing Tindall LB Georgia 6’2 230 – Channing Tindall has the combination of strength, speed, and Football IQ to man the MIKE position in this Under front. He aggressively triggers downhill against the run and shows excellent speed in space to defend the pass game.
Christian Harris LB Alabama 6’0 226 – Christian Harris makes good use of his defensive back background with his ability to cover RB out of the backfield and defend hook/curl routes in zone coverage. Harris is also a powerful downhill striker against the run.
On-Ball SAM – The SAM LB is different from the roles of the stacked LB. He lines up on the line of scrimmage usually at a 9 technique outside the TE. The SAM is responsible for setting the edge against the run, carrying the TE in coverage and rushing the passer. Versatility is a must for this position.
Jesses Luketa LB/Edge Penn State 6’3 253 – Jesse Luketa wore a variety of hats for PSU. He rushed the passer from a 2 or 3 point stance, played as a stacked LB and also dropped into short zone coverage. His versatility would play well at the SAM in a 4-3 Under.
Coverage on the Back End
To go with this 4-3 Under front I chose to run Cover 1 Robber behind it. Cover 1 coverage has 2 CB playing man coverage with a single high safety over top. The other safety acts as the Robber coming down from depth to take away the intermediate routes. This coverage disrupts the timing of routes and gives the defensive line another split second to get to the QB. The CBs need to be physical at the line of scrimmage and fast enough to carry vertical routes. The Safeties need to have range to stay over the top of the defense and the awareness to quickly identify route concepts.
Cornerbacks
Kaiir Elam 6’1 191 CB Florida – Kaiir Elam is an aggressive, physical CB that likes to beat on receivers at the line of scrimmage. He shows the speed to run with receivers down the field and disrupt at the catch point.
Alontae Taylor 6’0 199 CB Tennessee – Alontae Taylor is another uber aggressive and competitive player that will make receivers fight for every yard. He likes to press receivers at the line and is physical throughout the route stem.
Safety
Kerby Joseph 6’1 203 S Illinois – Kerby Joseph was used as a single high defender for Illinois. He shows the range to stay over top of the defense and the ball skills to track and make a play on the ball in the air. He also shows good eye discipline to read the QB and keep himself from being manipulated.
Tycen Anderson 6’2 209 S Toledo – In the Toledo defense Anderson was used in a variety of ways. He played the overhang defender and covered receivers and TE out of the slot. He also showed the ability to trigger on underneath routes from depth. This ability should fit well working as the Robber in a Cover 1.