According to an AP article on it, it stated he can be replaced. That's where I got the answer. It is the AP after all, so who knows.
New Jersey was loose with the law and allowed Torricelli to be switched after the ballot deadline. Texas was tight with the law and refused to allow DeLay to be replaced. I can't say what Florida would do, but they sure were loose with the laws in 2000.
Also, the US Supreme Court refused to get involved in New Jersey. They may have second thoughts now that this is becoming a standard practice in more than one state -- to drive out an opponent after filing deadlines in order to win an unopposed race.
-PJ