Leeds chairman Ken Bates admits the fan who assaulted Sheffield Wednesday keeper Chris Kirkland has damaged the image of the club.
Aaron Cawley, 21, of Cheltenham, was jailed for four months after he admitted assaulting Kirkland during the 1-1 draw on Friday night.
Cawley ran on to the pitch just after the Leeds equaliser, and shoved Kirkland in the face.
Leeds have subsequently banned Cawley from Elland Road for life.
Bates, speaking before Cawley's appearance at Sheffield Magistrates Court on Monday morning, said: "What is encouraging is that the vast majority of Leeds fans were as appalled by what happened as everyone else.
"The idiot who ran on the pitch better not go anywhere near Elland Road again. There are a lot of people angered by what he did.
"We have been working hard as a club to improve our image over the past few years. But this guy has done so much damage to that. It isn't fair on the overwhelming majority of Leeds fans."