Beginning in 1902, Mason City hosted numerous semi-pro teams in the years before minor league baseball, playing as the Hubs and Claydiggers. Minor league baseball began in Mason City with the Mason City Cementmakers, who joined the 1912 Iowa State League. The Mason City Cementmakers won the 1912 Iowa State League Pennant. Mason City finished 38–27, 1st in the five-team Iowa State League under Manager Frank Barber. Mason City finished ahead of the Fort Dodge Boosters, Estherville, Iowa, Emmetsburg, Iowa and Clear Lake Fish Eaters. The Iowa State League permanently folded after the 1912 season. In 1915, Mason City gained a franchise in the Class D Central Association, replacing the Galesburg Pavers, who had folded. The Mason City Claydiggers played in the league opener at Mason City on May 6, 1915. The Claydiggers were defeated in the opener 2–0 by the Muscatine Muskies. In attendance for the opener were Iowa GovernorGeorge W. Clark, Adjutant General Guy E. Logan and Central Association President M. E.Justice. Mason City Mayor Truman Potter threw out the first pitch. In their first season of play in the Central Association, the Mason City Claydiggers finished 58–63, 4th in the regular season under Manager Harry Bay. The 1915 standings were: Burlington Pathfinders, Muscatine Muskies, Keokuk Indians, Mason City Claydiggers, Cedar Rapids Rabbits, Marshalltown Ansons, Waterloo Jays, Clinton Pilots. The Mason City Claydiggers finished sixth in the eight-team Central Association in 1916. Mason City was 50–73 under Manager Harry Bay. The 1917 season was the final one for the early Central Association. The league folded after the 1917 season and reformed in 1947. The 1917 Claydiggers finished 54–38, 2nd in the Central Association under Manager Dan O'Leary. The league received permission and ceased play on August 7, 1917. Mason City was without a minor league team until 1994, when the Mason City Bats finished 19–41 in the Independent four-team Great Central League.
Ballpark
Mason City teams played at Hanford Park. After the Claydiggers folded, the grandstands were disassembled and the lumber used at the local fairgrounds. Hanford Park was located at the southwest corner of Pierce Avenue & Highway 106, Mason City, Iowa.