Kristaps Porzingis pulled up with a calf injury against the Miami Heat on Monday and limped to the locker room.

The injury took place late in the second quarter with Boston leading, 47-31. Porzingis took a pass from Jaylen Brown in a halfcourt set, then lost control of the ball while pulling up in apparent pain. He immediately raised his hand to be taken out of the game and started to limp.

The Celtics listed him as doubtful at halftime with right calf tightness. ESPN’s Adrian Wojnarowski reported during the third quarter that Porzingis is scheduled to undergo imaging on Tuesday and that early indications are that he did not suffer an Achilles tendon injury.

Porzingis appeared to tweak something two possessions prior to leaving the floor. He came up limping in transition after a Celtics miss.

He remained in the game only to leave the floor with a limp moments later. Al Horford took his place in the starting lineup in the second half.

The Celtics entered Monday with a 2-1 lead in the first-round playoff series and took a 53-36 lead into halftime. The injury is a potentially significant blow for Boston if Porzingis is forced to miss extended time.

Porzingis was key for the Celtics as the rolled to the NBA’s best regular-season record at 64-18 in his first season with Boston. He averaged 20.1 points, 7.2 rebounds and 1.9 blocks per game while shooting 51.6% from the floor and 37.5% from 3 in the regular season.