The big social issue in sports in 1867 came about when the colored Pythian Base Ball Club of Philadelphia attempted to join the Pennsylvania State Association of Base Ball Players. They had some support within the baseball establishment, most notably from Thomas Fitzgerald, who had until recently been the president of the Athletic Base Ball Club of Philadelphia, as well as a radical Republican (which in those days meant crazy ideas like civil rights for blacks) newspaper publisher who had stumped for Lincoln before it was trendy. Despite this support, an informal canvas of delegates showed that the Pythian’s application would going to be rejected, and on Fitzgerald’s advice the club withdrew its application. (Martin Luther King, Jr., would later have some pointed commentary on this phenomenon, though not writing of the Pythians in particular.)
This story is pretty well known, among those interested in 19th century baseball history. Less well known is that the National Association of Base Ball Players took note, and debated the issue, despite there no being an actual application by a colored club. The National Association ruled that no club with colored members could join.
The stated reason for this ruling was a desire to keep politics out of baseball. This is, of course, bullshit. The decision to support the strong against the weak is itself political. The idea that you can just stick to sports and avoid politics is exactly the same sort of bullshit.