Offensive Trends Could Force Drastic Changes to 49ers Defensive Scheme

Football is cyclical.

Jun 11, 2025; Santa Clara, CA, USA; San Francisco 49ers defensive coordinator Robert Saleh speaks to the media following a team OTA at Levi's Stadium. Mandatory Credit: D. Ross Cameron-Imagn Images | D. Ross Cameron-Imagn Images

When Robert Saleh first got hired as the 49ers' defensive coordinator in 2017, the NFL was a passing league. Now, it's much different.

Back then, very few teams were seriously committed to running the ball. Most teams employed three wide-receiver formations and utilized only a few run-blocking concepts. That's why in 2019, Saleh and the 49ers installed the Wide 9 defense and hired defensive line coach Kris Kocurek, whose motto is to play the run on the way to the quarterback. Meaning the defensive linemen fire out of their stances with the intent to rush the quarterback on every play. Only when they see a handoff do they adjust.

Saleh used a Wide 9 defense in New York when he was the head coach of the Jets. And then he faced Kyle Shanahan and the 49ers in the season opener last year, gave up 147 rushing yards and a touchdown to Jordan Mason and lost 32-19.

Sep 9, 2024; Santa Clara, California, USA; San Francisco 49ers head coach Kyle Shanahan (right) greets New York Jets head coach Robert Saleh (left) after the game at Levi's Stadium. Mandatory Credit: Darren Yamashita-Imagn Images | Darren Yamashita-Imagn Images

"I think teams are going more to the run," Saleh said this week. "You kind of feel that. All of us defenses, we're all sitting back playing a bunch of 2-shell (coverages). It was kind of like a punch in the mouth Week 1 last year when Kyle ran the ball 38 times on us -- it was death by a million paper cuts. I do think these coordinators are starting to get back to running the football and establishing that to get people from playing those 2-shells. It does seem to be the evolution as it's going back to the run game."

Now, teams tend to use formations with two tight ends. And the ones who still use three-wide-receiver formations often have a quarterback who is a threat to run. Which means you don't see many pared-down one-back running games anymore. Offenses have gotten more sophisticated with their ground attacks.

So the Wide 9 doesn't have much benefit. The 49ers need to make run defense their primary concern -- they don't need to play the run on the way to the quarterback anymore. That's the wrong approach.

Aug 9, 2025; Santa Clara, California, USA; San Francisco 49ers defensive coordinator Robert Saleh watches from the sidelines in the first quarter against the Denver Broncos at Levi's Stadium. Mandatory Credit: David Gonzales-Imagn Images | David Gonzales-Imagn Images

So Saleh has a choice. He could load the box with an eighth defender, but then he'll be vulnerable to long passes. Or, he could play five defenders on the line of scrimmage and keep both of his safeties deep.

Don't be surprised if Saleh chooses option No. 2. He showed some five-man fronts in the preseason and could use them heavily Week 1 against the Seahawks, who want to run the ball.