Negro League

The Negro League was a professional baseball league that Joshua Gibson, the star player for the Pittsburgh Crawfords, played in. The Doctor saw the Crawfords play many times. (PROSE: Illegal Alien)

Behind the scenes
"Negro leagues" collectively describes the professional baseball leagues of predominantly African-American players that played during Major League Baseball's decades of unofficial racial segregation. The Pittsburgh Crawfords, referred to by the Doctor in PROSE: Illegal Alien, played in the Negro National League during Gibson's tenure with them.