We connected with The Historical Negro League Baseball Site, a closed group on Facebook. Thanks to Will Clark in this group, we found this amazing link to more information:

The Negro Baseball Leagues and the Baltimore Elite Giants

Elite Giants, Negro Leagues Baseball team group portrait on field.
Not dated
Paul S. Henderson, 1899-1988
8 x 10 inch black and white negative
Baltimore City Life Museum Collection

An excerpt from the above article:

Professional baseball teams began to form after the Civil War, but professional leagues had not developed yet.  There were black teams and white teams in the segregated society. Both amateur and professional teams were organized and black and white teams played each other occasionally, although typical of the times, they mostly observed the color barrier. The rules were also relaxed at times when players crossed the color line. Some players even crossed the color barrier for the rest of their careers.

So glad we found this group. Enjoy the above article and link. There is LOTS more information here.

Negro League Baseball History Links