The San Francisco 49ers are expected to hire Robert Saleh to be their next defensive coordinator, and that means he’s probably going to be taking the style of defense he was taught with him. Who taught him about defense? Among others: Pete Carroll and Gus Bradley. Saleh was the defense quality control coach for the Seattle Seahawks from 2011-2013 and the linebackers coach for the Jacksonville Jaguars from 2014-2016.

On Monday, ESPN’s Adam Caplan explicitly stated that the 49ers are expected to switch from their 3-4 defense to Bradley’s 4-3 base with elements of a 3-4, just like he learned from Carroll in Seattle.

For those asking: 49ers expected to run 4-3. Same as Gus Bradley's defense. Some coaches say has elements of a 3-4 on tape. — Adam Caplan (@caplannfl) February 14, 2017

David Fucillo of Niners Nation broke down some of the personnel questions San Francisco will need to address in order to run the new defense:

For the Niners, their OLB’s (if they were actually any good) could slot into the OTTO and LEO spots, though they don’t really have the pure pass rusher you’re typically looking for at LEO (guess would be that Harold is the current guy most suited for that spot). Though since I would imagine there’s going to be a solid amount of roster turnover anyway, there will probably be quite a few new additions. I think the biggest questions relating to the current roster I would have would be: 1) What happens with Buckner and Armstead in base (both would be best suited for that strong-side 5-tech DE role and don’t really have a clear fit for another spot in the defense, but of course, would be fine when they’re in sub-packages); and 2) Do they move Jimmie Ward to FS as their Earl Thomas (could see him doing well in that spot)? Everyone else can either fairly easily slide into a similar role in the 4-3 scheme or doesn’t matter.

This comes as little surprise, since owner Jed York has been clearly looking to tap the Seahawks resources for the last two months. That includes interviewing Seattle assistant Tom Cable for the head coaching position that went to Kyle Shanahan (who worked under Dan Quinn) and also speaking to two Seahawks front office execs about the opening at GM that ultimately went to John Lynch.

Don’t be surprised when the 49ers sign a couple free agents from Seattle next month. They’re gonna need help running this new defense. (Perhaps Jeron Johnson and if they really want to be obvious about it, Mike Morgan.)