A new rule floated by Florida gambling regulators holds a price tag of $50 million a year and could cost hundreds of jobs, according to a lawyer representing several of the state’s cardroom operators.

The regulation in question, proposed late last month by the Division of Pari-Mutuel Wagering, would make a number of changes and effectively do away with controversial “designated player” card games that have been lucrative for pari-mutuel facilities across the state.