Complex sentence: Moreover, the revised free agency rules gave players the leverage to demand being paid in U.S. dollars-until about the early 1990s, Canadian teams were able to pay most of their players in Canadian dollars.
Split into simpler sentences: Moreover, the revised free agency rules gave players the leverage to demand being paid in U.S. dollar. Until about the early 1990s, Canadian teams were able to pay most of their players in Canadian dollars.