The official launch of NBA free agency is still a good dozen days away.

The business of NBA restricted free agency, however, has already changed a bit.

Before the RFAs of 2015 even hit the open market, their corner of the annual offseason frenzy that commences every July 1 is quietly but unmistakably taking on a different look.

We got a glimpse of it this week, just as the Golden State Warriors were about to clinch their first championship in 40 years. Warriors general manager Bob Myers was asked by reporters at a Tuesday morning shootaround, hours before Golden State's decisive Game 6 victory, about his team's chances of hanging on to restricted free agent-to-be Draymond Green.

And Myers, on cue, resisted the urge to say what GMs typically say in these situations -- the stock line about how the Warriors intend to match any offer that comes to its versatile and vocal frontcourt stalwart.

"I can't comment, per league rules, on that specific question," Myers said when pressed about Green.

That stance was no accident.

ESPN.com has learned that the NBA, as far back as November, issued a memo to all teams warning them that the National Basketball Players Association has officially taken the position that the well-worn "we'll match any offer" reflex strategy and its corresponding intent to discourage interest in a particular RFA is a circumvention of the salary cap.

The league's memo, sources said, took the rare step of further cautioning teams that, while the NBA itself doesn't concur with the NBPA's view, league officials see enough potential merit in the union's stance to advise those who persist with match-any-offer chatter that they could be opening themselves up to legal action.

Since the inception of restricted free agency in the NBA in 1999, teams have routinely disseminated such statements -- both to media members and rival teams -- in an attempt to convince teams to not even bother with offer sheets.

It's a tactic that has long gone unchallenged, but sources say that agents Rich Paul and Mark Termini of Klutch Sports -- sensing a climate change given the willingness and assertiveness of new union head Michele Roberts to speak up for her constituency since taking over in July 2014 -- urged the NBPA to challenge the way teams have historically dropped loud hints about their matching plans in an attempt to chill the market for restricted free agents.

It remains to be seen, of course, whether any player agents or the union will actually go to the lengths of lodging a full-fledged legal grievance against a team that slips into old habits this summer. The reality, though, is that going the legal route suddenly has the NBPA's strong backing.

And it would appear that teams have already begun to proceed with more caution.

On Thursday, at a postseason news conference in the wake of the Cleveland Cavaliers' loss to Golden State in the NBA Finals, Cavs GM David Griffin poked fun at his own vulnerability at the dais, knowing he would be getting questions about three restricted free agents from his own roster: Iman Shumpert, Matthew Dellavedova and, most notably, offensive rebounder extraordinaire Tristan Thompson.

"I'm absolutely certain I'm going to be fined for what I say here today about free agents," Griffin quipped, "so please keep in mind I'm really not allowed to negotiate these things now."

The hope of agents out there is that the mere threat of legal action winds up leading to more offer sheets for a class of RFAs that features Kawhi Leonard, Jimmy Butler, Reggie Jackson, Tobias Harris, Khris Middleton and Patrick Beverley on the list of headliners alongside Green, Thompson and Shumpert.

It's too soon to say if that's what happens.

But the possibility certainly exists if the thinly veiled "stay away from our player" talk we've heard for so long is curtailed.