John Salley --SMOKE WEEEEED ... Legalize It In NBA!!!

If Kevin Durant wants to smoke weed for medical reasons, he should be able to BLAZE UP without fear of punishment from the NBA ... so says 4-time NBA champ John Salley.

John is a HUUUGE proponent of medical marijuana -- in fact, he was rockin' a pro weed sweatshirt at LAX this weekend -- and explained why NBA teams should EMBRACE the ganja.

So, with Durant getting into a car that seemed to have had weed in it this weekend ... Salley says the OKC Thunder should "buy a dispensary for him" to help the superstar heal from a foot injury.

FYI -- weed is still outlawed by the NBA, but in a recent interview with GQ, Commissioner Adam Silver seemed pretty open minded about changing the policy.