If Mike Mularkey is retained, he may be down a man on his defensive staff from last season. Reportedly Hue Jackson has pinned Titans' defensive coordinator Ray Horton atop his wishlist.
Browns HC Hue Jackson targeting Tennessee's Ray Horton as his DC, but uncertain whether Titans will grant permission to leave, per source.— Adam Schefter (@AdamSchefter) January 14, 2016
Horton held the title of defensive coordinator last season for the Titans, but everyone had the feel that Dick LeBeau was the one calling the shots. Horton was the Browns defensive coordinator in 2013 before leaving to join Ken Whisenhunt.
It's unclear right now who is safe on the current Titans' staff, but it looks like they all have contracts that run through February. I wouldn't expect many to return if Mularkey is brought back, but even then Mike may want to move some things around. We probably won't see the Browns granted permission until the Titans make a final decision on Mularkey.