BOSTON — Boston Celtics forward Gordon Hayward had surgery on his broken left hand, a move that is expected to keep him out for about six weeks.

The team sent out a release late in the first quarter of Monday’s game against Dallas that Hayward had successful surgery “to repair a fourth metacarpal fracture in his left hand.”

Hayward broke his hand in a collision with Spurs forward LaMarcus Aldridge in the second quarter of Saturday night’s game in San Antonio. He left the game and did not return.

“He was frustrated. He was down,” Coach Brad Stevens said at the team’s morning shootaround. “But this isn’t like last time.”

Hayward, 29, missed all but five minutes of the 2017-18 season after breaking his leg in the first quarter of the opener against Cleveland.

Forward Jayson Tatum also said Hayward seemed frustrated after the latest setback.

“I feel bad for him. He was just getting back to being himself,” Tatum said. “It’s a bummer.”

Hayward returned last season and played in 72 games, most of them off the bench, and averaged 11.5 points and 4.5 rebounds – far short of his numbers before the injury. He had been closer to his peak performance in the first seven games this season, averaging 19 points, four assists and a career-high seven rebounds before the latest injury.

“He’ll be out a little bit and go from there, and he’ll come back,” Stevens said before the game. “This is not a season-ending thing. There’s a silver lining whenever you miss games is you’re more fresh in the end. He’s playing great, but there’s other guys that are ready to step up and fill the void.”

His teammates know how well he was playing.

“The crazy thing is he was playing unbelievable,” forward Enes Kanter said. “I said in the beginning of the season, ‘He’s back, 100%. And he’s going to shock the world.’ He was shocking the world. Now he’s got that injury.”

Kanter was cleared to return Monday against the Dallas Mavericks after missing seven games with a left knee contusion.