Deshea Townsend is a former member of the Steelers in the coaching ranks
If Mike Tomlin likes to stick with guys he knows and repeat some trends, then Deshea Townsend would make a lot of sense. He was always the second cornerback opposite of Ike Taylor back in the day, but both brought some great qualities to the position. Townsend is currently a defensive backs coach for the Jacksonville Jaguars and could make sense for the Steelers.
Tomlin likes to hire guys he knows and having a connection to Pittsburgh would help. Townsend does not have any experience calling plays on defense, but Tomlin likes to make the calls a lot of the time anyway. Townsend would be a good figurehead type of defensive coordinator and someone that Tomlin would like to work with.
Brandon Staley could get some looks once he gets fired after the season
There are some Head coaches on the hot seat and there might not be one sitting on a burning chair more than Brandon Staley right now. He has not worked out with the Chargers and has made some bad calls as their coach. He is a defensive mind and was a quality defensive coordinator before taking the top job in LA.
Staley could be a nice addition to add some extra leadership and power to the Steelers coaching staff. This would be an unusual hire for Tomlin as he does not allow people with prior authority on his staff to challenge him based on previous hires, with Brian Flores being the exception. Staley would be able to provide that and try to rebound his career in Pittsburgh.