5:20pm: ESPN.com's Marc Stein tweets that the provision also applies to trades involving three or more teams, so no deals involving both the Clippers and Celtics will be allowed next season.
4:11pm: The Celtics and Clippers have officially agreed on compensation and completed a deal that will make Doc Rivers the new head coach in Los Angeles. However, according to Ken Berger of CBSSports.com, the agreement includes one notable detail that hadn't been previously reported. Berger tweets that the Celtics and Clippers have agreed that they can't exchange players until after the 2013/14 season.
We knew that the league was likely to disallow any trade involving Kevin Garnett heading to the Clippers, since the CBA doesn't permit one deal to be contingent on another, and the NBA viewed Garnett as connected to Rivers. Still, the agreement reported by Berger is even more extreme, eliminating the possibility of any deals between the two clubs for at least a year.
Of course, that doesn't necessarily mean that Paul Pierce couldn't still end up on the Clippers. L.A. can't trade for him, but if Pierce is bought out before June 30th, he could theoretically still sign with the Clips as a free agent.