BOSTON >> Boston Celtics guard Isaiah Thomas will miss the rest of the playoffs because of a hip injury, further damaging — if not outright dooming — the team’s chances in the Eastern Conference finals against Cleveland.

The Celtics made the announcement Saturday, a day after Thomas left Game 2 at halftime. The Cavaliers already led by an NBA-record 41 points at that point, and they went on to a 130-86 victory that gave them a 2-0 lead over the top-seeded Celtics in the best-of-seven series.

The Celtics said Thomas injured the hip in March and aggravated it in Game 6 of the East semifinals against Washington. The swelling increased during the first two games against Cleveland, team doctor Brian McKeon said, and Thomas was limping on the court just before halftime on Friday night.

“Isaiah has worked tirelessly to manage this injury since it first occurred,” McKeon said. “In order to avoid more significant long-term damage to his hip, we could no longer allow him to continue.”

Thomas did not travel with the team to Cleveland for Game 3 on Sunday. The Cavaliers could finish off the sweep with victories in Cleveland.

“He was pretty despondent not to be able to play,” Boston coach Brad Stevens said Friday night. “He’s a tough guy, and for him to have to sit is really hard.”

A 5-foot-8 guard who was the last selection in the 2011 NBA draft, Thomas emerged as a star this season, averaging nearly 29 points and leading the league in fourth-quarter scoring.

Last week, he earned All-NBA second team honors, the first Celtics player to be selected to the All-NBA first or second team since Paul Pierce in 2009.

He was scoring 23.3 points per game in the playoffs — including a 53-point game vs. Washington that was one shy of John Havlicek’s franchise postseason record.

This despite the death of his sister on the eve of the first-round series against Chicago, an emotional blow that also took a physical toll through the cross-country travel to Washington state so he could be with his family and attend the funeral.

And having his front tooth knocked out in Game 1 of the conference semifinals against Washington, forcing him to spend several more off-days in oral surgery.

“Can’t say enough about #thelittleguy Isaiah—Thomas,” assistant general manager Mike Zarren said on Twitter. “Last month one of the guttiest performances (thru all sorts o’ stuff) I’ve ever seen.”