It is collectively bargained. But PDX has the same fundamental question that I always have. The players' union (i.e. people who are already NBA players) does not seem to have a particular incentive to induce the NBA to shift the demographic of NBA players younger. It only puts them out of jobs earlier. I always thought that the players union, knowing that the NBA opposed drafting players out of high school, took the opposite position so that they could "concede" it during negotiations and get something else in return. But no, they appear to really want it. I don't get it, frankly.