In an act of protest, NBA referees turned their jerseys inside-out Friday night and wore No. 62 - the number assigned to a disciplined colleague.

Referee Michael Henderson's bad call at the end of Wednesday night's Lakers-Nuggets game was publicly acknowledged Thursday by the NBA.

Henderson was taken off three job assignments and summoned to the league office, the referees' association said.

``An unprecedented job action was taken against one of their colleagues, so an unprecedented response was necessary,'' said Larnell McMorris, a spokesman and negotiator for the National Basketball Referees Association.

Referees at all 10 NBA games Friday night were expected to wear Henderson's number, McMorris said.

The NBA released a statement from deputy commissioner Russ Granik saying any referees taking part in the protest ``will be subject to appropriate discipline.''

Henderson, in his second season as an NBA official, mistakenly whistled a shot clock violation after an attempt by Denver's Andre Miller brushed the rim and was rebounded by a teammate.

The officials huddled and ruled it an inadvertent whistle, resulting in a jump ball. The Lakers won the tip and made the game-winning shot with 3.2 seconds left.

``This was an unfortunate call at a highly critical point in the game, and we very much regret the error,'' NBA vice president Stu Jackson said his statement Thursday. He was not immediately available for comment Friday night.

McMorris said Henderson's three-game punishment was unprecedented.

``It's inconsistent with the performance evaluation standards that the league introduced to initiate communication between supervisors and referees,'' McMorris said. ``This has never occurred for a bad call.''

The referees are currently in the final season of their five-year collective bargaining agreement with the NBA.