New 49ers defensive line coach Kris Kocurek is switching up how the team’s defensive front lines up. That change comes with a ripple effect that stretches out to the team’s linebackers, and how that group lines up in the 49ers’ defense.

Last season the 49ers’ defensive scheme typically had the SAM linebacker playing on the ball outside the defensive end. They were essentially a fifth defensive lineman responsible for setting the edge on the strong side of the formation. Kocurek will have the team in more ‘wide 9’ looks, meaning the defensive line will stretch out wider, eliminating the need for the fifth on-ball defender.

Head coach Kyle Shanahan told reporters that this change will make the WILL and SAM linebacker spots more interchangeable than they were the previous two years.

“When you mix in a lot more nines and stuff you have three linebackers off the ball, which makes those guys a lot more interchangeable,” he said according to a transcript distributed by the team. “So, now it’s just true two outside backers and you’ve got a MIKE who plays in the middle. We can still put guys on the ball, whether it’s the SAM or the WILL, depends if they’re to the three technique or the bubble.

“But, it’s a lot, they’re all the same bodies now. That SAM linebacker had been, it’s more what we went to in the year, when we started playing more [LB Mark] Nzeocha, Malcolm, when we traded [Buffalo Bills LB] Eli [Harold]. And now that we are playing more nines we can put them a lot more off the ball so they’re a lot more interchangeable.”

Given that the WILL is on the weak side of the formation and the SAM is on the strong side, their duties on a given play will vary, but the ability to move players between those two spots is now easier than it was.

A direct result of this change was rookie linebacker Dre Greenlaw lining up at SAM with the first team during Tuesday’s practice. He ran with the starters due to injuries to Kwon Alexander, Fred Warner and Malcolm Smith. The initial thought was that Greenlaw would play WILL because he physically and athletically profiled for that spot.

Now the new wide defensive line will allow smaller, faster linebackers like Greenlaw to swap between SAM and WILL rather than sticking solely to the latter.

New positional versatility could change how the 49ers elect to shape their roster. The needs at SAM linebacker have changed, and may push players like Elijah Lee and Greenlaw up the depth chart since their value now spreads across two positions.

This new linebacker setup will be an intriguing new wrinkle to follow throughout the offseason program and into training camp.