Al Sharpton -- NBA Should Take Clippers from Sterling

Reverend Al Sharpton is calling for the NBA to investigate Donald Sterling ASAP -- telling TMZ Sports, "No one should be allowed to own a team if they have in fact engaged in this kind of racial language."

Sharpton is calling for the league to make an investigation into Sterling its #1 priority -- adding, "We are prepared at National Action Network to rally in front of the NBA headquarters if this matter is not immediately dealt with."

TMZ Sports broke the story ... Sterling -- who owns the L.A. Clippers -- went off on his girlfriend for hanging out with black people in public and told her NOT to bring black people to his games.

We shot Sharpton moments ago at La Guardia airport and he gave more details on the possible rally.