The Toledo Mud Stockings joined the American Association in 1884 after the Northwestern League folded. These were the days before the professional baseball leagues merged to form Major League Baseball.

The Mud Stockings are primarily remembered historically for having Moses Fleetwood Walker on their squad, thus making him the first African-American to play professional baseball at the major league level.

Walker suffered a season ending injury halfway through the 1884 season and his team went out of business. He later played in the International League in 1887 until Cap Anson flatly refused to step on the field if Walker played. Shortly thereafter, both the American Association and the National League blocked African-Americans from playing professional ball until Jackie Robinson broke the color barrier in 1947.