Midwest League The Midwest League is a Class - A minor league baseball league which operates in the Midwestern United States . History . Six teams – the Belleville Stags , the Centralia Cubs , the Marion Indians , the Mattoon Indians , the Mount Vernon Braves , and the West Frankfort Cardinals – began operating as the Class D Illinois State League in 1947 . The league changed its name to the Mississippi - Ohio Valley League in 1949 after the Marion team moved to Paducah , Kentucky . The league added teams in Clinton and Dubuque , Iowa , in 1954 and was renamed the Midwest League two years later . After the Illinois - Indiana - Iowa League folded in 1961 , teams from Appleton , Burlington , and Cedar Rapids joined the Midwest League for the 1962 season and remain in the league today . In 1963 the Midwest League became a Class A league after the minor league classification structure was reorganized . In 1976 the Midwest League contracted from ten teams to eight when teams in Danville and Dubuque were eliminated . In 1982 the league expanded to 12 teams by adding the Beloit Brewers , the Danville Suns , the Madison Muskies , and the Springfield Cardinals . The Peoria Suns replaced the Danville Suns in 1983 , and acquired their current name , Peoria Chiefs , the following year . The league began splitting its season into two halves and expanded to 14 teams in 1988 with the addition of franchises in South Bend , Indiana , and Rockford , Illinois . During the 1990s several teams changed cities as Major League Baseball placed higher standards on minor league baseball facilities ; franchises in smaller cities were sold to new owners who moved those teams to new ballparks in larger cities . Kenosha , Madison , Rockford , Springfield , Waterloo , and Wausau lost teams during this decade while Battle Creek , Dayton , Fort Wayne , Grand Rapids ( West Michigan ) , Kane County , and Lansing gained teams . The Fort Wayne TinCaps are the oldest franchise in the league , having begun as the Mattoon Indians in 1947 and playing in Keokuk , Iowa ; Wisconsin Rapids , Wisconsin ; and Kenosha , Wisconsin , before moving to Fort Wayne , Indiana , in 1993 . The Clinton LumberKings have been in one city longer than any Midwest League team , having called Clinton , Iowa , home since 1954 . The Southwest Michigan Devil Rays moved to Midland , Michigan , and became the Great Lakes Loons prior to the 2007 season . On September 2 , 2008 , Minor League Baseball announced that two teams would transfer from the fellow Class A South Atlantic League to the Midwest League . These two teams are the Lake County Captains ( an affiliate of the Cleveland Indians playing in Eastlake , Ohio ) and the Bowling Green Hot Rods ( an affiliate of the Tampa Bay Rays playing in Bowling Green , Kentucky ) . Season structure . The league plays a 140 - game schedule that begins on the first Thursday in April and ends in early September , usually on Labor Day . The season is divided into two halves and accordingly each team ' s record is reset in the middle of the season . The two halves are separated by the Midwest League All - Star game . Players are selected from teams in each division , allowing the best members of the Eastern and Western divisions to face off against each other . Since 2000 it has been divided into an Eastern Division and a Western Division , with four teams from each division qualifying for the first round of playoffs . The two teams with the best record from each division in each half of the season are awarded these eight playoff spots . The first two rounds of playoffs are best - of - three series ; the league championship series is a best - of - five .