The Boston Celtics announced Thursday that center Kristaps Porzingis had surgery to repair the rare leg injury he suffered during the NBA Finals, and that his recovery time would be five to six months -- meaning he won't return until well into the start of next season for the defending champions.

Porzingis, 28, suffered a torn medial retinaculum allowing dislocation of the posterior tibialis tendon in Game 2 -- an injury the team described as "rare" in its news release.

He sat out Games 3 and 4 before returning to score five points in 16 minutes in Game 5 as Boston claimed the NBA title with a 106-88 victory over the Dallas Mavericks.

"I don't care," he told ESPN the night of Game 5, after saying it would take a long time for him to recover from. "I will fix it. This is the most important, and after my injury healing, and all that, it's totally worth it."

Boston acquired Porzingis from the Memphis Grizzlies a year ago this week, sending out Marcus Smart and also getting back two first-round picks in a deal that the Celtics hoped would allow them to diversify their offense and help them finally get over the hump and claim a record-setting 18th NBA title.

Porzingis wound up fitting in well with the Celtics, averaging 20.1 points and 7.2 rebounds while shooting 51.6% as Boston rolled through the NBA with a league-leading 64 wins before going 16-3 in the playoffs and winning the championship.

When he suffered the injury in the Finals, he'd already missed 10 playoff games after suffering a calf strain in Game 4 of the first round against the Miami Heat, an injury that knocked him out until Game 1 of the NBA Finals.

He told ESPN after Game 5 that he had concerns about possibly suffering an even more serious injury by coming back and playing, but that he was determined to be part of Boston's title-winning run.

"Of course," Porzingis told ESPN. "I think something could have happened, for sure, especially compensating now on the other leg now, which I just came back from.

"There was definitely some added risk, but I didn't care. I was like, 'I want to give everything I can and then fix it after if I need to.'"

With Porzingis sidelined, Boston will be expected to start Al Horford at the beginning of next season until Porzingis is healthy, while Neemias Queta is on a non-guaranteed deal. Boston's two backup centers who saw minutes with Porzingis sidelined during the playoffs, Xavier Tillman and Luke Kornet, are both unrestricted free agents.