CAMDEN. N.J. — Philadelphia 76ers center Joel Embiid missed Game 1 of the Eastern Conference semifinals against the Boston Celtics with a sprained right knee.

Embiid was at the team’s morning shootaround on Monday and was listed as doubtful before being ruled out shortly before tipoff.

The Sixers have had the longest break of any NBA team after they swept the Brooklyn Nets last Saturday. Embiid was hurt in Game 3 and missed the next game.

“If I was a betting man, I would probably say doubtful for at least Game 1, but we’ll see,” Rivers said Saturday at the 76ers’ facility in New Jersey. “He has to get better. He did nothing (today). Just wasn’t able to and obviously we were hopeful for today.”

The 29-year-old Embiid, from Cameroon, averaged 33.1 points this season to win his second straight scoring title. He also averaged 10.2 rebounds and tied a career high with 4.2 assists per game. He played in 66 games, the second-highest total of his career.

Embiid missed two games in the second round last year and another in the first round in 2021 with various injuries, on top of the two he missed to begin the 2018 playoffs with an orbital fracture and another in 2019, also with a knee problem.

Embiid averaged 36.8 points and 11.8 rebounds in four games this season against the Celtics.

Information from The Associated Press was used in this report.