Football 101 - Basics of the 3-3-5 Defense

Note: This is a new series intended to assist fans in learning more about the basics of Old Dominion football and the game they play. Our goal is to give all fans a better understanding of the basics of our program, the offensive and defensive schemes and concepts and the verbiage used so they can further enjoy the program we're building at Old Dominion. Since this is an introductory level tutorial, it might not be for everyone. But we hope you enjoy it and appreciate our want to help educate the entire fanbase on the fundamentals of this game we all love. To read the first release of this series, click here.

By Robert King

Defensive coordinator Blake Seiler has become a staple of Old Dominion football, having been the defensive coordinator all six seasons of the Ricky Rahne Era. He is now the longest tenured Defensive Coordinator in our program's brief history.

During this time, Seiler has had some great accomplishments and coached great players. In 2024, the Seiler defense forced turnovers in 10 of 12 games, including 5 vs East Carolina. The Monarchs had 5 players on the All Sun-Belt team to include Koa Naotala (2nd Team), Jahron Manning (3rd Team), Kris Trinidad (3rd Team), Mario Thompson (Honorable Mention), and Denzel Lowry (Honorable Mention). 

In 2023, Seiler’s defense forced 21 turnovers and were 4th in the Sun belt in rush defense. This was a special year for the Monarchs as Linebacker Jason Henderson led the country in tackles for the 2nd straight year with 170 and was an All-American (1st Team by some 2nd Team by Others) as well as 1st Team All-Sun Belt Conference. ODU was the only team in the country to have 3 players record over 100 tackles with Wayne Matthews III (135) and Terry Jones (107) joining Henderson during this historical season. The success has much to do with Seiler’s 3-3-5 defense.

Verbiage:

Now, before we get into the basics of this defense, we feel like we should explain the verbiage first so we can all be on the same page throughout the article.

Blitzing is a defensive tactic where more defensive players rush the quarterback than the offensive line has to block them.

Stunting is when two defensive linemen switch gaps by twisting at the snap of the ball. A linebacker and defensive lineman can twist as well.

Slanting is when a defensive lineman moves laterally across an offensive lineman’s face to the adjacent gap. Generally, the entire defensive line will slant right or slant left.

Cover 0 is a man coverage scheme where all defensive backs are assigned to a specific receiver, with no deep safety playing back to help cover deep routes. Cover 0 is often used in conjunction with blitz making it high risk/high reward.

Cover 1 is a defensive coverage characterized by man-to-man coverage of the five eligible receivers, with one safety playing deep in the middle of the field for support.

Cover 3 is a zone coverage scheme where three defensive backs cover the deep thirds of the field, while linebackers and safeties handle the underneath zones.

Dropping 8 is when 3 linebackers and 5 defensive backs drop back into coverage, giving the defense an extra man in coverage. A signature of the 3-3-5 defense.

Stacking means the linebackers are lined up directly behind the defensive linemen, creating a stacked look.

Fundamentals:

The 3-3-5 defense is a defensive alignment using 3 down linemen, 3 linebackers, and 5 defensive backs. The defense is known for its' deception, versatility in blitz packages, and ability to drop extra defenders in coverage. The defense has been highly effective against the spread offense and has been nicknamed the “spread defense”. The idea is the defense is filled with smaller, athletic players who can both blitz and drop in coverage, creating multiple looks and variables to confuse the quarterback. A Sam linebacker can line up at the line of scrimmage as if he is going to blitz, but then drop back into coverage to give the secondary extra support.

There is a wider range of blitz packages and coverages that the quarterback has to be accountable for. In the same defensive front, you can rush 6 and drop 5 to create heavy pressure, or rush 3 and drop 8 to keep everything in front of the coverage players. Linebackers can show blitz and drop into coverage, or blitz from the second level.

Pictured; examples of defensive line slant

Defensive linemen can slant or stunt out of this defense, creating that much more confusion. There is an endless stream of options in this defense, but everything is run out of a base 3-3-5. This is why smaller, athletic personnel fit this scheme. You’re not beating the other team with physicality and size, you’re beating them with deception, speed, and strategy that forces the quarterback to make split second decisions against an unconventional defense.

Pictured; example of a defensive line stunt

Personnel:

The 3-3-5 defense requires personnel to be smaller and more agile. Players must blitz and cover regardless of position.

The defensive line consists of a nose tackle and two defensive ends. The nose tackle can be lined up head up on the center (0 technique) or on the outside shoulder of the center (1 technique). This player is primarily responsible for A gaps and needs to be stout against the run. The defensive ends are typically longer and more athletic and able to bend as they rush the passer. The defensive ends will be lined up in 5 techniques (outside shoulder of tackle), 4 (head up on tackle), or 4i (inside shoulder of tackle). Coach Seiler aligns these players in various combinations. All of them are asked to stunt and slant and show great athletic ability. 

Photo courtesy of CoachParker.org

The linebackers are referred to Sam (Strong Side), Mike (Middle), and Will (Weak Side). These 3 players will align to the strong, middle, and the weak side of the field. All 3 of these linebackers are versatile playmakers who have closing speed, coverage skills, and can make plays in the backfield. Their range and physicality make them some of the best athletes on the field.

The 5 defensive backs consist of 2 cornerbacks and 3 safeties (who often line up in the middle of the field and hash marks). All 5 are asked to blitz and play man & zone coverage.

Coach Seiler shifts the alignment at all 3 levels based on personnel and spacing. But the combinations are played out of a base 3-3-5 and are intended to disguise the post snap responsibilities of the defensive players. 

Summary:

If executed correctly, the 3-3-5 defense can be a headache for quarterbacks and offensive coordinators alike. The deception, manipulation, and speed of the players can make for a long, confusing game for the opposing offense. It requires players that are both quick thinking and light of foot. Deception is the essence of this defense by mixing looks, blitzes, and coverages to keep the offense hesitant and confused. Defensively it requires timing and execution. Players need to be fast and versatile enough to pose a serious threat pre-snap and change responsibilities post-snap.

The downside of the defense is if the players are out of position this can lead to big gains by the offense. Short passes can lead to high YAC (yards after catch) and touchdowns. Last year, no starting defensive lineman weighed more than 280 pounds and, as established, there are only three on the field. So if these three linemen are not effective at pressuring the quarterback, this allows receivers to get open for big gains. And if they don't get off their block, it can make the defense susceptible to quarterback scrambles. Also, it is necessary for the team to tackle well or it will be vulnerable against the run due to the lack of size.  

Old Dominion returns 6 starters on defense, including an experienced and deep linebacking unit led by a now healthy Jason Henderson. Old Dominion gave up 28 pts per game last year, losing 6 games by 8 points or less, so the defense is taking it upon themselves to close out games this year. Old Dominion has been strong in red zone defense under Coach Seiler. They have held teams scoreless roughly 20% of the time in the last two seasons in the red zone, enough to finish 4th in the Sun Belt. Old Dominion held teams to a 50% 4th down conversion percentage which was enough to finish 5th in the Sun Belt. The defense has been clutch and now with experience and depth returning, the defense has high expectations for 2025!

Robert King is an ODU alum (class of 2021) and a lifelong ODU sports fan, having attended football games since 2009 and basketball games since the days of the ODU fieldhouse. Currently, Robert is a local P.E. teacher and HS football coach. He spent his college years working as an ODU football intern, scouting and evaluating high school prospects. In his spare time, he enjoys attending concerts, traveling, movies, and outings with family and friends.