Porzingis suffered the injury on Nov. 24 in a loss to the Orlando Magic and has missed Boston's past three games.
Coach Joe Mazzulla said last Sunday that the former All-Star would be reevaluated "after a week or so."
Porzingis has been enjoying a strong first season with the Celtics, averaging nearly 19 points on 54.7% shooting from the field.
For the Pacers, star guard Tyrese Haliburton missed Saturday's win over the Miami Heat with a non-COVID illness and a bone bruise in his right knee and is listed as questionable for Monday's quarterfinal with the knee injury. Pacers forward Jalen Smith is out with left knee and heel injuries.
The Pacers and Celtics both won their groups and face off as the East's Nos. 2 and 3 seeds, respectively. The winner of Monday's tournament game will advance to the semifinals in Las Vegas.