Kyrie Irving left the Brooklyn Nets' 115-107 win over the Chicago Bulls after colliding with Nikola Vucevic.
Irving was cleared of a concussion, though an initial x-ray returned inconclusive.
Irving will get a second x-ray on Wednesday.
"They need a further scan. I don't know if it's the swelling or what," said Steve Nash on Irving's condition.
The Nets play the Spurs on Wednesday.