The Latvian power forward suffered a "rare" leg injury in game two of the NBA Finals earlier this month and will go under the knife to repair the problem.
"The injury doesn't allow for consistent play at the level required for Olympic competition. Surgery will be performed in the coming days, and further updates will be provided when available," the Celtics said.
Porzingis suffered a 38-day layoff after injuring his right calf in April, before coming off the bench to play in game one of the NBA Finals for the Celtics.
He played in game two but suffered a "torn medial retinaculum allowing dislocation of the posterior tibialis tendon in his left leg".
That injury ruled him out of games three and four, although he returned from the bench to play 16 minutes in game five as the Celtics wrapped up a 4-1 series victory.
