He played Junior "B" for the Brantford Penguins in 1979-80 and major junior for the Peterborough Petes from 1980 to 1984. The St. Louis Blues chose him 50th overall in the 1982 NHL Entry Draft. Posavad turned pro with the Peoria Rivermen in 1984-85. The following season he made his debut in the NHL playing six scoreless games for the Blues. In 1986-87 he played two more games for the Blues. He retired in 1988 following another season with the Rivermen.