 The Red Wings placed Pronovost with the Windsor Spitfires, one of their junior teams in the Ontario Hockey Association (OHA), beginning in 1947 – 48. The Spitfires were a dominant team that season; Windsor finished with the best record in the OHA but lost the championship series to the Barrie Flyers after Detroit was forced to recall Windsor's goaltender, Terry Sawchuk, to one of their minor league teams. Pronovost believed that the Spitfires would have won the league title and gone on to play for the Memorial Cup if they hadn't lost Sawchuk. At the same time, Pronovost also played for the Detroit Auto Club team in the International Hockey League (IHL). At the time an amateur league, the IHL based most of its teams in Detroit or Windsor and the majority of players were affiliated with the Red Wings. Playing in the two leagues prepared Pronovost for the rigors of an NHL schedule. He played 52 games that season, and 51 in 1948 – 49. Pronovost permanently moved to defence during his tenure with the Spitfires.
