Ken Whisenhunt will start to hire his staff over the next few days. Jason LaCanfora says he would like to hire John McNulty as his offensive coordinator McNulty was the quarterbacks coach for the Buccaneers in 2013. He spent the 4 years prior to that as the receivers coach in Arizona.
McNulty did a good job with rookie QB Mike Glennon this past season. He was also the offensive coordinator at Rutgers in 2008.
Butler has been the linebackers coach with the Pittsburgh Steelers since 2003. It is hard to say how he would be as a defensive coordinator since he hasn't ever been one, but he has spent a lot of time working for Dick LeBeau. You could do a lot worse for a mentor.
These aren't guys that most people have heard of, but doesn't mean they won't do a good job. It will be interesting to see how this all shakes out.