The Boston Celtics on Tuesday announced a new injury to one-time All-Star center Kristaps Porziņģis — "a torn medial retinaculum allowing dislocation of the posterior tibialis tendon in his left leg."

The statement describes the condition as a "rare injury." His availability for the rest of the NBA Finals "will be determined day-to-day," the team said, a few hours before officially listing Porziņģis as questionable for Game 3. Boston leads the Dallas Mavericks in the series, 2-0.

"I'm optimistic," Porziņģis told reporters on Tuesday in Dallas, where Game 3 is scheduled for Wednesday. "As I said, I will do everything I can to be out there tomorrow. ... Nothing's going to stop me, unless I'm told I'm not allowed to play. That's the only reason I would not be out there, but tomorrow we'll see."

The Celtics said the injury occurred at the 3:27 mark of the third quarter in Game 2. This play — a box-out collision with Mavericks center Dereck Lively II — is the only evidence of any potential leg injury:

Porziņģis moved more gingerly on his left leg after the collision, particularly on the next several possessions, as he was attempting to close out on shooters. He remained in the game for an additional 2:45, subbed out, retreated to the locker room, and then played 3:26 more in the fourth quarter.

"He's doing everything and anything he can to be ready for the game tomorrow," said Celtics coach Joe Mazzulla. "It's a serious injury. At the end of the day, our team and the medical team is not going to put him in any bad situations. We've taken the decision to play out of his hands because of the importance of him. He's going to do everything he can to play, and we're going to leave it up to our medical team."

Just how likely is Porziņģis to play in Game 3?

"I have no idea," said Mazzulla.

Prior to Game 1 of the NBA Finals, Porziņģis missed 36 days, including both the Eastern Conference semifinals and finals, with a soleus strain in his right calf. His latest injury is "unrelated," the team said.

The Celtics are +25 in Porziņģis' 44 minutes over two games of the NBA Finals. They are even with Dallas in the 52 minutes he has been on the bench. During the regular season, Boston outscored opponents by 11.2 points per 100 possessions in Porziņģis' minutes; that number increased to 11.8 with him off the floor.

Porziņģis' absence would mean increased minutes for 38-year-old Al Horford, who started at center in Games 1 and 2 of the NBA Finals. Luke Kornet could see his first minutes off the bench in the series.