DALLAS — The Celtics ruled out starting center Kristaps Porzingis before Game 3 of the NBA Finals Wednesday night.

Porzingis had been listed as questionable after suffering a tendon dislocation in his left foot/ankle late in the third quarter of the Game 2. He has a “torn medial retinaculum allowing dislocation of the posterior tibialis tendon in his left leg,” according to the team. On Tuesday, Porzingis and Celtics coach Joe Mazzulla said his status for Game 3 would be up to the team’s medical staff.

Mazzulla also described the injury as “serious” Tuesday, a notable departure for a coach who is usually tight-lipped about player injuries. The media retinaculum is connective tissue helps holds tendons in place, including the posterior tibialis, the largest tendon in the ankle that attaches the calf muscle to bones in the foot.

Playing on the hurt ankle could have incurred risk of an injury in his right leg, according to sports medical experts who cited the body’s tendency to overcompensate. Porzingis just missed more than a month with a calf strain in his right leg. If he played, he would likely have dealt with notable pain and potentially some instability in his left ankle, as well.

His status for Game 4 on Friday is unclear.

Porzingis told reporters Tuesday he got hurt while fighting Dallas center Dereck Lively for a rebound off a Celtics free throw in Game 2, a collision that forced his left leg to bend sideways at the knee and ankle. He added he would only be sidelined if the medical staff told him to sit.

“From my side, as I said, nothing’s going to stop me unless I’m told not to or not allowed to play,” Porzingis said Tuesday. “That’s the only reason I (won’t) be out there.”

The Celtics are expected to start Al Horford in Porzingis’ place for a third straight game. Boston swept the Pacers in the Eastern Conference Finals with Horford in the starting lineup. Porzingis missed the East Finals and entire second round with the right calf strain, which he suffered in the first round against Miami on April 29.

Tip-off for Game 3 is set for 8:37 ET.