If we were running a 4-3 Kerrigan would most likely make the switch to DE or you might see Lanier there.
It would seem a guy like Stacy McGee would be a best fit in the 4-3 as a DT. He's 335 and has some athleticism, but doesn't have the ability to play straight over the nose.
So, I think the personnel is here to make that transition.
Brown, Foster, Anderson, etc. could be the LBs in a 4-3.
But I don't think you will see the team make that change.
At least under this administration.
They seem set in place on both sides of the ball.
Shawn Lauvao and Ryan Grant are HC favorites and are kept ahead of other players despite being 'meh' contributors.
DeAngelo Hall at 34 and hopping on one leg is still on the team, although hanging on by one finger on the PUP list.
Any other team facing Cravens uncertainty at safety, like the Steelers or Bucs would have gone out and made a deal for some insurance there.
But we allow safety, left guard and defensive tackle remain problem areas.
We simply refuse to acquire TWO safeties that can play together with no question marks or 'transition' periods to go through.
We refuse to upgrade from Lauvao in the draft or free agency.
We refuse to admit that Ryan Grant is simply a good practice and camp player whose impact in NFL games that count is next to zero.