There are two key rules in play here.
One, you can’t trade a player for a coach. That is not actually in the Collective Bargaining Agreement (according to Larry Coon, CBA expert), the document doesn’t mention the idea at all, but the league is saying since it is not outlined as permitted it is not allowed.
Two, you can’t have any side, wink-wink deals tied to a trade. That is clearly laid out in the document.
So the Clippers can’t just throw two first round picks as compensation for Doc Rivers as part of a DeAndre Jordan for Kevin Garnett trade, as has been proposed and the teams had basically agreed to.
“The teams are aware that the collective bargaining agreement doesn’t authorize trades involving coaches’ contracts…
“The teams know that,” Stern said. “It has been confirmed to them. … It can’t be gotten around by breaking it up into two transactions.”
“If you think those, at this point — having been all over the media for the last week — are separate transactions … I have a bridge that I would very much enjoy selling to you,” Stern said.
That leaves the Clippers and Celtics trying to find a workaround. The Celtics don’t want Doc Rivers to leave them as coach and head to another team without compensation, but how to get that to pass muster with the league remains a real sticking point now.
This is different then when Stern blocked the trade of Chris Paul to the Lakers — at that time he was acting as the defacto owner of the Hornets (remember George Shinn sold the team to the league which sold it a year later to Tom Benson, the trade was proposed while the team was in the league’s control). This time he’s acting as commissioner. Not that many people are going to make that distinction.