The 1890 Chicago Pirates baseball team was a member of the short lived Players' League. They compiled a 75–62 record, good for fourth place, ten games behind the league champion Boston Reds. After the season, the league folded, and the Pirates were bought out by the Chicago Colts.

The 1890 Boston Reds baseball team was a member of the short-lived Players' League. They compiled an 81–47 record and won the league championship. After the season, the league folded, but the Reds were invited to join the American Association for the following season and folded after a single season with players dispersed to other AA teams.