Wouldn't really make much sense, or difference, to do that mid-season. I don't agree. It MIGHT not make a difference, but it very well could. Just a different voice leading the defense, calling the plays/schemes. It couldn't hurt if that's going to be the end result anyway. Maybe, but you aren't gonna be able to bring in a real DC mid-season, so you're stuck with someone temporary...that doesn't exactly command authority.