The Negro American League of 1951 is considered the last major league season .
The last professional club , the Indianapolis Clowns , operated amusingly rather than competitively from the mid-1960s to 1980s .
The Negro American League of 1951 is considered the last major league season and the last professional club , the Indianapolis Clowns , operated amusingly rather than competitively from the mid-1960s to 1980s .