On February 26, 1957, Wilhelm was traded by the Giants to the St. Louis Cardinals for Whitey Lockman. At the time of the trade, St. Louis manager Fred Hutchinson described Wilhelm as the type of pitcher who "makes us a definite pennant threat ... He'll help us where we need help the most." In 40 games with the Cardinals that season, he earned 11 saves but finished with a 1–4 record and his highest ERA to that point in his career (4.25). The Cardinals placed him on waivers in September and he was claimed by the Cleveland Indians, who used him in two games that year.