Prigioni sprained his right ankle at the end of the first quarter in Wednesday's regular-season finale against the Atlanta Hawks.
The Knicks said X-rays on Prigioni's ankle came back negative. Knicks coach Mike Woodson said after the game that he was unsure whether Prigioni would be available Saturday against the rival Celtics.
Prigioni went down with 51 seconds left in the first quarter. He appeared to roll his ankle on a jump-stop near the rim.
Prigioni, 36, has started the past 18 games, and Woodson had planned to start the Argentinian alongside Raymond Felton in New York's playoff series against Boston.