Davis underwent X-rays, and New Orleans coach Alvin Gentry said the results were negative and more will be known about Davis' injury Tuesday.
Davis -- who had 40 points, 18 rebounds and 3 blocks in 29 minutes during New Orleans' 110-96 victory at Madison Square Garden -- was driving toward the basket when O'Quinn slapped down hard from behind. Davis went flying into the stands behind the basket, and the center said he hit his hip on a chair.
Officials determined that O'Quinn's foul was a flagrant foul 2, which led to his automatic ejection with 1:16 remaining in the third quarter. This came less than two minutes after Carmelo Anthony was ejected for two consecutive technical fouls for arguing during a timeout with 2:35 left in the third.
Davis made both free throws after the flagrant foul to push the Pelicans up 87-63 and did not return afterward.
"Bruised hip, a hip pointer," Davis said, describing his injury. "[It was] a hard foul. I really didn't look at it yet. I saw what he did but it is what it is."
Davis said he will undergo treatment leading up to the Pelicans' next game at Brooklyn on Thursday.
"Obviously it is going to be sore," Gentry said. "We will know more tomorrow. ... It's a hard foul. I didn't actually see the play. I saw the replay. I don't think [O'Quinn] is a dirty player by any stretch of the imagination. Just a hard foul. [The officials] thought it was over the top."
Monday night marked the fifth time this season Davis left a game early because of injury, and the second time he left and did not return. The 23-year-old has missed two full games this season, with one a result of planned rest.
ESPN's Justin Verrier contributed to this report.