The NBA has added a rule that will close up an officiating loophole that was exposed in a game between the Celtics and Blazers on Dec. 30.

The Blazers inadvertently had six players on the floor against the Celtics. With 10.1 seconds left in the first half, Boston frantically tried to cover up defensively on an in-bounds play, but Portland's Travis Outlaw broke free and dunked.

The basket counted, and the Celtics were livid. Crew chief Mike Callahan, with referees Rodney Mott and Zach Zarba, could not disallow the points because it was a non-correctable call. Portland was assessed a technical foul and the Celtics ended up with one point in return.

"I was just incredulous," Joel Litvin, league president with responsibility of the officiating, said. "I said, 'This can't be.' It's amazing no one picked it up."