Sitake doesn't like to babysit so why bring in a newbie like Poppinga at this moment unless you get someone else there to help him.
There's no reason to circle back around to former BYU guys. Go get a G5 guy. There's nothing preventing you from doing that. Get an FCS coach to be a co-coordinator or AHC and he can help the new DC if that's the route you're going.