 Holcomb was appointed as the general manager of the Chicago Mustangs, a United Soccer Association franchise owned by Arthur and John Allyn.After the Mustangs folded following the 1968 season, Holcomb was reassigned to the Chicago White Sox, another of the Allyn brothers' business entities, as its public relations director.He was promoted to replace Ed Short as general manager in September 1970, the last month of a season in which the White Sox finished with its worst record in team history at 56–106.