From 1890 to 1946, the exclusion of black players from major league baseball was an unwritten rule. This stark reality, however, didn't prevent blacks from competing on town teams, and from eventually forming their own leagues. In the Red River Valley, a black man named "Bish" Dorsey played prominently throughout the late 1890s with Grand Forks teams. But the versatile Dorsey was conspicuously absent from the Red River Valley League of 1897. He appeared in some exhibition games that summer with amateur local teams, but did not appear for the Grand Forks Senators. Since the Red River Valley League of 1897 was officially sanctioned by the National League, it is likely that influence from league officials kept Dorsey out of uniform.
While prejudice in baseball was widespread, the role of Adrian "Cap" Anson in the segregation of baseball was in no way minor. One of baseball's brightest stars in the late 1800s, Anson was in his 27th season as a player in 1897, also serving as manager of the Chicago Colts of the National League. The man sometimes called "Pop" was highly regarded as one of the game's wise and influential veterans. During Anson's prime years in baseball, he refused to play against Moses Fleetwood Walker, a black minor leaguer, on at least two separate occasions. Cap was unsuccessful in preventing Walker's inclusion in an 1883 exhibition game, but succeeded in keeping Walker out of an 1888 contest. Not long after the second incident, the unofficial color line was drawn by the National League and American Association, preventing future participation of blacks at baseball's highest level for over a half century. The color barrier would significantly limit opportunities for blacks in the minor leagues, as well, as it undoubtedly did with Bishop Dorsey in the summer of 1897.