The baseball color line excluded players of Black African descent from Major League Baseball and its affiliated Minor Leagues until 1947 (with a few notable exceptions in the 19th century before the line was firmly established).
Before 1885 at least three African-American men played in the major leagues: William Edward White, whose light skin color allowed him pass as white, played one game for the Providence Grays in 1879; Moses Fleetwood Walker, an openly Black man who played for the Toledo Blue Stockings of the American Association between May 1 and September 4, 1884; and his brother, Weldy Walker, who played five games with the Toledo club between July 15 and August 6, 1884. Baseball officials essentially drew the color line against Fleetwood Walker. African-Americans had been excluded from major league baseball since 1884 and from white professional minor league teams since 1889. Following the 1891 season, the Ansonia Cuban Giants, a team composed of African-American players, were expelled from the Connecticut State League, the last white minor league to have a Black team.
The Brooklyn Dodgers broke the 63-year color line when they started future Hall of Famer Jackie Robinson at first base on Opening Day, April 15, 1947. The Boston Red Sox were the last team to break the line, when they inserted Pumpsie Green as an eighth-inning pinch runner in a July 21, 1959 game at Chicago.