Nets coach Steve Nash said Irving underwent an initial X-ray at the United Center in Chicago, but the results were "inconclusive."
"They need a further scan," Nash said, when asked to clarify what an inconclusive result meant. "I don't know if it's the swelling or what."
Irving is scheduled to have a second X-ray Wednesday morning. He is listed as questionable for Wednesday's game against the San Antonio Spurs.
Irving collided with Bulls center Nikola Vucevic in the third quarter while going up for a rebound and was hit in the face by a Vucevic elbow. Irving was down on the court for several minutes, pulling his jersey over his eyes, before being helped to a seated position. He then walked to the locker room without any assistance and did not return to the game.
Kevin Durant, who finished with a team-high 21 points, was one of the Nets players who huddled around Irving when he was lying on the court. Durant said after the game that he wasn't overly concerned when Irving was smarting.
"I thought he would be all right," Durant said. "He mixes it up a lot with the big fellas, so he might catch an elbow here and there. And Kyrie, he plays with such toughness and competitiveness. So, hopefully he gets checked out tomorrow, sees everything is all right and we can move forward."
Irving scored 13 points in 21 minutes. He was 4-of-10 shooting from the field and had three rebounds and five assists.