Turley made his professional debut that year in Minor League Baseball with the Belleville Stags of the Class D Illinois State League, pitching to a 9–3 win–loss record. He was promoted to the Aberdeen Pheasants of the Class C Northern League in 1949, and led the league in wins with 23, and strikeouts with 205. He split the 1950 season with the Wichita Indians of the Class A Western League and the San Antonio Missions of the Class AA Texas League. Turley led Wichita in the Western League playoffs. In 1951, he played for San Antonio. He appeared in the Texas League's All-Star Game, and was named the league's most valuable player at the end of the season. He struck out 22 batters in one game for San Antonio.