According to a Pennsylvania Commonwealth Court decision, an injured worker does not have to treat with a panel physician for 90 days unless the injured worker:
a) was given a list of six medical providers to choose from; and
b) signed a document both at the time of hire and at the time of injury indicating he or she would treat with one of the panel physicians
Treating with a specific company physician is never required under the Workers' Compensation Act, but you should also check any applicable collective bargaining agreement.
Questions? Feel free to give me a call at 724-837-0080. I'd be happy to help.