"The message we are sending out today is clear: Drugs and the NBA do not mix. If you want to get involved in drugs, you won't be involved in the NBA."

And that means "permanently dismissed," Commissioner Larry O'Brien went on in decreeing--jointly with the NBA Players Association--the penalty for proven criminal use or distribution of heroin or cocaine.

(A "permanently dismissed" player may appeal for reinstatement after two years.)

Strong medicine from the league in which surfaced the earliest reports of widespread drug abuse. Now, under the agreement signed by O'Brien and Bob Lanier, the Milwaukee Buck who is president of the players union:

* There will be a 60-day "amnesty period" up to this Dec. 31 during which a player may come forward and ask for help without losing salary or having to pay for treatment.

* A player who previously requested and received rehabilitation and again volunteers for treatment will be suspended without pay but receive no other penalty.

* "Any subsequent illegal use of drugs, even if voluntarily disclosed, shall result in immediate permanent dismissal from the NBA."

Said Lanier: "Professional basketball players are role models for young people all over the country, especially in the inner cities . . . We are setting a new standard, something that is absolutely essential in today's environment."