Today, most Defensive Coordinators will tell you that they are a spill team. That means they want to keep the ball going from band to band and prevent it from cutting the field.
All defenses also use the “contain the player” principle. The container player is the player who stops the spill. In our 4-3 Defense, we say that everyone on the defensive front is a spill-over player, and one player (on each side) is the “box” player.
The box player simply boxes the play and forces it back inside. That is in a perfect world, of course.
Many coaches use the term “Force” player instead of “Contain” or “Box” because they want that player to force the ball to change direction in some way. Either the ball carrier needs to go back inside, where the help is, or he needs to bubble the ball back to try to encircle the power player.
If the ball carrier is forced to back off, that gives the chase from the inside a chance to get there. It also means that the player is closer to freezing on the sideline. The sideline is the twelfth man in any soccer defense.
The 4-3 Defense is a true spill defense. Each player on defensive front 7 is responsible for the inner half of their allotted space. You should almost run into the blocker who is within your gap responsibility.
We call this “pulling the air” out of space. Think about when you put something in a zip-top bag and squeeze out all the air before sealing it. By removing all the space between him and the inside player in the gap, the ball is forced, in the worst case, to continue outside of it.
As the players squeeze the air in Defense 4-3, we are building a wall of defenders for the ball carrier to maneuver. There should be no place for him to return to the field. Even the slightest wrinkle can result in a mess. It only takes one player not to squeeze the air and we could have problems.
If each player does their job in building the wall, the ball will continue out of the spill and eventually collide with the container player or box player. The box player in our defense is normally the Strong Safe or the Free Safe on the playing side. We used Quarter Cover to engage the two safeties in the ground defense and create a 9-man Front.
The last piece of the puzzle is the deep defenders. If we use Quarter Coverage, we have a 9-man front and two defenders who should always be on top of Catchers # 1. These are the corners.
No defender who is responsible for a deep area of the field, or who is locked in man-to-man coverage, can be counted on for his running attacks. He is not in the spill, nor is he the box player. Our corners have the job of removing trick passes, play actions, and other plays where wide receivers could pose a threat even after offensive shows are running.