The San Francisco 49ers are revamping most of their coaching staff following the hiring of Jim Tomsula, and those changes are going to result in some significant adjustments on both sides of the ball. On the defensive side of the ball, it sounds like there will be a pretty big change. I spoke with Matt Miller, Bleacher Report writer and briefly a writer here back in the day, and he has heard the 49ers expect to make a switch to a 4-3 defense in 2015.
I don't know that anything is ever locked in stone, but it sounds like this is happening. There has been some chatter about it recently, so this would not be an altogether shocking development. The 49ers have not hired a defensive coordinator at this point, but they obviously would like to find somebody to fit the kind of scheme they envision playing moving forward. Aside from Jim Tomsula's promotion, it would appear they will have an entirely new defensive coaching staff in 2015.
If the 49ers end up making this switch, they will have to do a bit of maneuvering. They would likely be looking at a linebacker trio of Patrick Willis, NaVorro Bowman, and Chris Borland. Trent Baalke has previously said one reason the team signed both Willis and Bowman to big extensions was the fact that both could play linebacker in both 3-4 and 4-3 defenses.
The defensive line would likely include Aldon Smith and Aaron Lynch adding some weight to take over the end positions. We don't know Justin Smith's status, but if he were to return, he would likely handle one of the defensive tackle roles. They would also have Tank Carradine, Quinton Dial, Tony Jerod-Eddie, Glenn Dorsey and Ian Williams all as options along the line.
And while this is obviously important information, we know that they will likely still spend plenty of time in the nickel. The 49ers most prominent defensive package this past season was the nickel, so there would potentially still be enough familiarity with a sizable chunk of the defense. It will still impact their free agency and draft decisions, but they would at least have a base in place from which to work.