Here is the Constitution and Bylaws of the NBA:
http://fansided.com/2014/04/29/read-nba-constitution-laws-online/#!Gzm5V
Didn’t find anything that permits the NBA to ban Sterling or force him to sell the team under these circumstances. There is no arbitration clause, so if Sterling sues, he will get an injunction against the NBA denying him his right to run his franchise.
Section 2 of the Bylaws is interesting; especially 2.01, which requires the players to be of “good moral character”; whatever that means. Interestingly, there is no requirement for an owner to be of good moral character.
Even if it applied to an owner, which it doesn't; how could you ascribe his private conversations, with reasonable expectation of privacy, to serve as reasonable proof that he had violated the clause?
If he wants to do it he can put a hurt on the NBA.
If that's so or it, it's starting to look like a PR stunt by Commish Silver to appease and hold off the pressure from the NBA Player's Association the Media fanning the flames.