Boston Celtics center Kristaps Porzingis is out for Game 3 of the NBA Finals against the Dallas Mavericks on Wednesday because of what the team called a “rare injury” to his left leg.

The Celtics announced Tuesday that Porzingis has a torn medial retinaculum allowing dislocation of the posterior tibialis tendon in his left leg. The team said Porzingis’ status for the upcoming Finals games will be “determined day-to-day.”

The Celtics said the injury occurred in the third quarter of their Game 2 victory Sunday.

Porzingis could be seen wearing a sleeve and a brace of some sort on his left leg Tuesday, in addition to what appeared to be a brace on his left ankle. But he was walking without a limp and — as he often does — put on an optimistic tone when asked whether he thought he would be able to play in Game 3, when the Celtics will attempt to take a 3-0 lead and move to within one victory of a record-setting 18th NBA title.