 During the 1989-90 season, Thomas served as head coach of the St. Louis Blues' IHL affiliate, the Peoria Rivermen.In January 1990, the Blues temporarily brought him to St. Louis as a "de facto" goaltender coach to consult on the development of Blues prospects Vincent Riendeau and Curtis Joseph.That summer Thomas was officially named a Blues assistant coach, with specialty in goaltending, and was specifically hired by head coach Brian Sutter for his experience.