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.
In January 1990, the Blues brought Thomas to St. Louis as an informal goaltending consultant to work with prospects Vincent Riendeau and Curtis Joseph. Later that summer, he was officially appointed an assistant coach for the Blues, specializing in goaltending, hired by head coach Brian Sutter due to his experience.