The Louisville Colonels were a Major League Baseball team that played from 1882 to 1899 and were based in Louisville, Kentucky. The team played in the American Association from 1882 to 1891 and in the National League from 1892 to 1899.^[1] The team was known as the Louisville Eclipse from 1882 to 1884.^[1] The Colonels used 11 Opening Day starting pitchers in their 18 years as a Major League franchise. The first game of the new baseball season for a team is played on Opening Day, and being named the Opening Day starter is an honor, which is often given to the player who is expected to lead the pitching staff that season,^[2] though there are various strategic reasons why a team's best pitcher might not start on Opening Day.^[3] The Colonels had a record of 10 wins and 8 losses in their Opening Day games.

The first game in Colonels' history was played on May 2, 1882, against the St. Louis Browns, now known as the St. Louis Cardinals.^[4] Tony Mullane was the Opening Day starting pitcher for the Colonels in that game, which the Colonels lost by a score of 9–7.^[4] The Colonels' last Opening Day game was on April 14, 1899, against the Chicago Orphans, now known as the Chicago Cubs.^[5] Bert Cunningham was the Colonels' Opening Day starting pitcher for that game, which the Colonels lost by a score of 15–1.^[5]

Five pitchers made multiple Opening Day starts for the Colonels. Guy Hecker had the most Opening Day starts for the Colonels, with four, starting in every Opening Day game from 1883 through 1886.^[6][7][8][9] Toad Ramsey, Scott Stratton, Chick Fraser and Cunningham each made two Opening Day starts for the team.^{[5][10][11][12][13][14][15][16]} After making the Opening Day start in 1884, Hecker went on to achieve what is now known as the pitching Triple Crown by leading the American Association in wins, with 52, strikeouts, with 385, and earned run average, with 1.80.^[7][17] Hecker's 52 wins that season are 3rd all time among Major League Baseball pitchers.^[18] No Baseball Hall of Famers made Opening Day starts for the Colonels. However, as of 2011, Mullane's 284 career wins ranked 3rd among eligible pitchers who have not been inducted to the Hall of Fame, behind just Bobby Mathews and Tommy John.^[19]

The Colonels won one American Association championship, in 1890.^[1] That year, they played in the 19th century version of the World Series against the National League champion Brooklyn Bridegrooms, now known as the Los Angeles Dodgers, in a series that ended in a tie.^[20] Stratton was the Colonels' Opening Day starting pitcher that season, in a game the Colonels lost to the Browns 11–8.^[12]