49ers defense undergoing tweaks for next season

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?

First, it’s not their defense. Saleh learned it from Seattle Seahawks head coach ?Pete Carroll, who created it 10 years ago. This is key to understanding the change.

The NFL has evolved quite a bit the past decade. Ten years ago, most NFL offenses frequently kept two running backs on the field - a tailback and a fullback. Think Jim Harbaugh’s offense with Frank Gore and Bruce Miller. An old-school, smash-mouth attack. Carroll designed his scheme specifically to stop these two-back formations.

Now, most teams don’t even have fullbacks. Two-back formations almost are extinct. Only the 49ers and Patriots offenses use them consistently.

Last season, the 49ers defense faced two-back formations just 90 times out of 900 total plays. This does not count snaps at the goal line or snaps with five minutes left in games in which the 49ers were trailing by at least four points. At these times, teams use two-back formations to punch the ball into the end zone or run out the clock to win the game. Next season, almost every team the 49ers play features a one-back offense.

Saleh’s version of Carroll’s defense must evolve, and the Wide 9 alignment is the evolution.

Still, the Wide 9 isn’t totally foreign to the 49ers. They used it 138 times against one-back formations last season, and that number will skyrocket in 2019. The Wide 9 will be the 49ers’ primary defensive alignment, not just a change-up like before. During the rare instances when they face two-back formations, Saleh will ditch the Wide 9 and return to the previous scheme. Meaning the 49ers’ run defense should remain strong, and their overall defense might improve, especially early in the season.

Both in 2017 and 2018, the 49ers defense struggled the first half of the season, and improved during the second half. In September and October, the 49ers gave up 5.52 yards per play. Then, in November and December, the 49ers gave up just 5.17 yards per play.

The 49ers came into each season less prepared to defend the one-back offenses that have taken over the league. And the 49ers were less prepared because they spent all of OTAs, minicamp and training camp practicing against their own two-back offense. Very little of what the 49ers defense did during the offseason applied to what they had to do during the regular season.

This year, the 49ers have spent all offseason practicing their Wide 9 defense. They’re determined to master it before the season, rather than halfway into it. Determined to start off strong for the first time since ?Kyle Shanahan became the head coach. The past two years, the 49ers’ record in September and October is 1-15.

Is the Wide 9 the key to a quick start next season? Can moving one player two yards change the 49ers defense for the better? There’s reason to answer “yes” in both cases. We’ll find out soon enough.