Cleveland's star point guard, who only recently returned after missing 11 games with a broken finger, fractured a bone in his jaw when he took a hard fall in Friday night's loss at Milwaukee.
Irving travelled separately from the Cavs to New York so he could be fitted with a protective mask that he will wear in Saturday's game against the Knicks at Madison Square Garden. He said he arrived less than three hours before the start of the game, having only slept about four hours.
He said he wasn't in pain, and the only difficulty would be getting used to the mask, which earned him the nickname the "Dark Knight" in the locker room.
"It's just precautionary, as usual," Irving said.
Irving was injured when he was knocked down in the first quarter by Bucks forward forward Luc Mbah a Moute, who was called for a foul. Irving's face slammed into the floor, and he writhed in pain for several minutes before getting up and making two free throws. He stayed in the game.
At the end of the quarter, last season's NBA rookie of the year sat on the bench with a towel on his face, but he played 36 minutes and finished with a team-high 26 points.
Following the game, the Cavs indicated Irving would be on the flight to New York, but a CT scan at the Cleveland Clinic revealed what the team described as "a small left maxillary fracture."
Cavs forwards Tristan Thompson and Tyler Zeller are already wearing plastic protective masks for facial injuries sustained earlier this season.
This is the latest injury for Irving, who broke his hand this summer when he slapped a padded wall in frustration during a practice in Las Vegas. The 20-year-old's college career at Duke was limited to 11 games because of a severe foot injury.
Irving missed 15 games last season with a concussion and shoulder injury, but coach Byron Scott said he wasn't concerned with Irving's injury history.
"The one last night, you're going to the basket, sometimes you get hit and you're off balance. That's something that you can't help," Scott said. "The only one that I see that was really a problem was the one that he did in Vegas, because that was self-inflicting, but didn't cause him to really miss any time. This one is not going to miss any time as well, so other than that I don't see him as being, as most people say, injury prone or anything like that."
Friday's game was Irving's third since returning from the broken left index finger. He was expected to miss four weeks, but returned in three for the Cavs, who went just 2-9 without him. Irving said he won't change his playing style to prevent further injuries.
"No," he said. "Playing that way has got me this far."
AP Sports Writer Tom Withers in Cleveland contributed to this report.