According to The Athletic's Tim Cato, the 19-year-old is considered day-to-day.
Head coach Rick Carlisle said the injury is "not serious," per Eddie Sefkoe of Mavs.com.
Since being traded to the Mavericks on draft night in June, the Slovenian has established himself as the face of the franchise. The reigning EuroLeague MVP leads all rookies with 20.7 points and ranks second with 5.6 assists and 7.2 rebounds per game.
If Porzingis returns to full strength from his torn ACL, Dallas will have two of the most dynamic young players in the NBA.
The Mavericks are unlikely to enter the playoff picture and therefore have no reason to rush him back.