There's a lot being said about this altercation after the game on Saturday. Supposedly, this fan was holding up a sign that was either obscene or crude, but was made to put it away. Then when Jimbo passed by to go to the locker room, the fan taunted him. Coach Fisher responded with "Bring your a-- down here and say that."
During the post-game press conference, Coach Fisher didn't have much to say about the incident, other than he was defending his players, as they are like family. That part of the press conference starts around the 6:42 mark in this video: