The Atlanta Hawks have been fined $US100,000 after All-Star guard Trae Young was held out of an NBA Cup road victory over the Boston Celtics.

The Hawks listed Young with right achilles tendinitis on the injury report and cited the issue as the reason he was out of the side for the November 12 match.

Atlanta went on to a 117-116 victory over the defending NBA champions.

The NBA investigated the matter and, as it did with the Philadelphia 76ers and Joel Embiid this season, ruled that Young should have been available and on the court.

"Following an investigation, including review by an independent physician, the NBA determined that the Hawks held Young out of a game that he could have played in under the medical standard in the (Player Participation) Policy," the league said in a statement.

"The organization's conduct violated the Policy, which is intended to promote participation in the NBA's regular season."

Young has averaged 21.9 points with an NBA-leading 11.9 assists in 17 games this season. The November 12 game at Boston is the only one he has missed.

In seven seasons, Young has been named an All-Star three times and has averaged 25.4 points with 9.6 assists in 424 games for the Hawks, all starts.