The San Francisco 49ers are overhauling their coaching staff, and they have yet to hire a defensive coordinator or defensive line coach. The 49ers have run a 3-4 for some time now, but we don’t know what the plan is with the new coaching staff. In reality, teams rotate back and forth between a variety of fronts, and even a 3-4 team is likely to spend more time in a four-man front than a three-man front.
There is some confusion in the NFL scouting community about how to organize defensive lineman, and nose tackles are (literally and physically) right in the middle of it.