It is doubtful that Celtics player Kristaps Porzingis will return due to a calf injury

MIAMI – Boston Celtics center Kristaps Porzingis walked off the court before halftime to the locker room and is considered doubtful to return after suffering a right calf injury during Boston's fourth game with the Heat on Monday night.

Porzingis will undergo imaging on Tuesday, but early indications are that he has not suffered an Achilles injury, sources told ESPN's Adrian Wojnarowski.

Porzingis appeared to adjust something after catching a pass from Jaylen Brown late in the second half. Upon getting the ball, Porzingis began driving to his left and then scowled before quickly returning the ball to Brown and limping off the play. It does not appear that anyone touched Porzingis on the play during which he was injured.

While walking to the locker room with a support staff member, Porzingis briefly pulled his shirt over his face in apparent frustration.

The Celtics quickly issued an update stating that Porzingis was experiencing tightness in his right calf and was questionable to return to action. Porzingis did not join the rest of the team on the floor to start the third period.

Veteran big man Al Horford took his place in the starting lineup to start the second half.

The 7-foot-3 Porzingis, who joined the Celtics last season via a trade with the Washington Wizards, has fit in almost perfectly with his new team, averaging 20 points and seven rebounds a contest while giving Boston a more dangerous five-point offense. .

The Celtics lead the best-of-seven series versus Miami 2-1.