The 49ers have revamped their entire defense by moving one player two yards toward the sideline.
The 49ers will use a “Wide 9” defensive alignment most of the time next season. “Wide 9” simply refers to the strong-side defensive end. He lines up outside the tight end, as opposed to slightly inside the tight end, which is where he usually lined up the past two seasons for the 49ers.
This change looks minor — you may not even notice it when you watch the 49ers on television. But in terms of football philosophy, the change is drastic, the difference between Plato and Aristotle.
The Wide 9 defensive end is a “containment” player, meaning he forces the ball carrier to cut back into the middle of the defense. The Wide 9 alignment is strong against teams that run outside the tackles, but not as strong against teams that run up the gut. Every alignment has its strengths and weaknesses. This is the most profound truth of football.
The 49ers defense was designed to stop runs up the gut the past two seasons. Defensive coordinator Robert Saleh packed his defensive linemen close together, plugged the middle of the field and tried to force ball carriers to run outside the tackles where the defense neutralized them. This philosophy was successful — the 49ers defense gave up the seventh-fewest yards per carry in the NFL each of the past two seasons.
So why did the 49ers change their defense?
Click here to find out why.