In 1891, Borchert Field was still known as Athletic Field and was home to the Milwaukee Brewers who were a Major League team playing in a league that no longer exists today, called the American Association. After the AA folded, the Brewers joined the Minor League Western League. This would prove to be an important move, because the Western League left the National League's Minor League system and became a renegade Major League, with intentions to rival the National League. The Western League renamed itself the American League and began play as a Major League system in 1901 with the Detroit Tigers.