In 1867, just two years after the Civil War, the National Association of Base Ball Players voted to exclude clubs with Black members — the first formal color line in organized American sport. The vote was framed as avoiding "any controversy whatever." Before this vote, integrated play had occurred. Black players had competed against white players in barnstorming games, local leagues, and pickup contests. The exclusion was a deliberate choice by white baseball administrators, not an expression of any natural order.
Through the 1870s and 1880s, individual Black players found footholds in white minor leagues. Moses Fleetwood Walker and his brother Weldy Walker played for the Toledo Blue Stockings in the American Association — considered a major league — in 1884. Moses Fleet Walker is considered the last Black player in major league baseball before the color line hardened completely. By 1887, Cap Anson — the most prominent player of his era — had used his influence to pressure teams to release Black players and refuse to take the field against integrated opponents. The color line was complete. It would hold for 60 years.