True, but Tressel would fight it because it could potentially mean millions to him, and of course that would go to court and get public and ugly, so the most likely scenario is a negotiated buyout. Nobody wants their dirty laundry aired like that.
If Tressel is canned he won't fight it. Violating rules of conduct and the law is most certainly in his coaching contract as grounds for termination without compensation. If he violated NCAA rules and the school acts to terminate him because of that then he has no grounds to sue.
If they fired him because of falling short in BCS games then he could sue for rightful compensation. In this scenario the former would be the case. He wouldn't drag it out since no judge would accept the case.
A more recent and somewhat similar example was Mike Leach at Texas Tech. However, Leach was fired amid allegations of player mistreatment and there were no formal sanctions from the NCAA. Thus, it is debatable whether he violated the codified code of conduct in his contract since that dealt with legal and NCAA sanctions. Tressel's contract and all of them for Div 1 coaches contain clauses which allow justifiable dismissal if sanctions are levied. It's not like Tressel is in the drivers seat at all.