1890 Louisville Colonels season

The 1890 Louisville Colonels baseball team finished with an 88–44 record and won the American Association championship. The previous season, the Colonels had lost 111 games, the most any team in the Major Leagues had lost up to that point (the record was broken during the 1890 season by the Pittsburgh Alleghenys, who lost 113 games). When the Colonels won the 1890 pennant, it was the first time in major league history that a team had moved from last place to first place in the span of a single year. The Colonels accomplished this largely because of the contributions of two young pitchers, Scott Stratton and Red Ehret. Several other players, including outfielder Jimmy Wolf, first baseman Harry Taylor, second baseman Tim Shinnick and shortstop Phil Tomney, provided strong support. Veteran manager Jack Chapman was also lauded in the press for providing his young team with steady guidance. Yet another factor in the Louisville club's success was that the competition in the American Association was diluted by the advent of the Players' League and by the fact that two of the best AA teams from 1889 moved over to the National League in 1890.

Although the Louisville club is listed as the "Louisville Colonels" in most sources, the club was actually known as the "Louisville Cyclones" during the 1890 season. A deadly tornado (referred to as a cyclone in 1890 parlance) swept through Louisville in March 1890, killing 115-120 people. When the local baseball team began showing signs of dominance early in the 1890 baseball season, the club was dubbed "the Cyclones." It continued to be referred to by that name the rest of the season, then switched back to "Colonels" the following year.

After the season, Louisville played the NL champions, the Brooklyn Bridegrooms, in the 1890 World Series. The Bridegrooms were one of the teams that had jumped to the NL, and had been the champions of the AA in 1889. The World Series wound up in a 3–3–1 tie.