The Dodgers left Spooner unprotected in the 1957 minor league draft, and he wound up being claimed by the St. Louis Cardinals. For the 1958 season, Spooner was demoted to the very lowest rung of minor league ball, playing for Dothan in the 'D' level Alabama–Florida League, appearing in 9 games. He also played two games for Houston at the AA level that same season, but that ended his professional career. Spooner attended spring training in 1959, but retired before the season started.