Golden State Warriors forward Draymond Green was ejected for the third time this season during the 119-116 defeat by the Phoenix Suns.
Green, 33, swung an arm in the face of Suns centre Jusuf Nurkic and sent him to the floor during the third quarter.
The referees reviewed the incident and ruled it a flagrant foul 2, which leads to an automatic ejection.
Last month Green was given a five-game ban for putting Minnesota Timberwolves centre Rudy Gobert in a headlock.
He was also ejected for two technical fouls against the Cleveland Cavaliers.
Green apologised to Nurkic after the game, saying he “didn’t intend” to hit him.
“He was grabbing my hip, so I spun away and unfortunately I hit him,” he said.
Green had scored two points and made two rebounds and two assists in 17 minutes before his ejection, with the Warriors leading 65-60.
“We need Draymond. He knows that and we have talked to him. He’s got to find a way to keep his poise and help his team-mates,” said Warriors coach Steve Kerr.
“Draymond is still a really good player. We need him if we are going to be a really good team.”
Stephen Curry scored 24 points for Golden State at Footprint Center in Phoenix, but defeat was their 11th in 15 games.
Devin Booker recorded 32 points and seven assists for Phoenix, who won for the first time in three matches.
The Los Angeles Lakers, who won the NBA Cup on Sunday, were beaten by the Dallas Mavericks in a thrilling contest where the lead changed hands eight times.
Luka Doncic starred for the Mavericks with his eighth successive 30-point game – he scored 33 points and made 17 assists and six rebounds.
The four-time NBA All-Star stayed on the court despite rolling his ankle and suffering a bloodied lip in a physical contest.
“I’m not going out in a game like this, no way,” said Doncic. “When you’re playing against the best you want to stay on the court.
“This was an amazing team win. We’ve got so many guys out. Everybody stepped up. Everybody played hard.”