The reason was a rare 10-second violation on a free throw attempt.
The poor-shooting Howard has always been deliberate at the line, and referee Bennett Salvatore called a violation for taking too long to attempt his second shot late in the second quarter Wednesday at Charlotte.
As the crowd jeered, Howard tossed the ball away from any official. Salvatore immediately gave Howard a technical.
If the call is upheld by the league, Howard will sit out Sunday's nationally televised game against East-leading Chicago.
Howard served a one-game suspension on March 7 after picking up his 16th technical.