Al Horford has been upgraded to probable against Toronto after missing the past two games while navigating the league's concussion protocol.
Celtics big man Aron Baynes hit Irving while trying to defend a Kemba Walker shot attempt in the first quarter of Friday's game. After fouling Walker on a drive, Baynes spun to box out, and his right elbow smashed Irving, who collapsed to the floor clutching his face.
Irving was attended to by Celtics trainer Art Horne and left the court clutching a towel over his bloodied face. He was monitored for a potential concussion.
Boston was already playing without Gordon Hayward (ankle) and Horford. Including Irving, that's $76.2 million worth of unavailable talent.
Even without their stars, the Celtics won their 11th straight game by rallying from 18 down to top Charlotte.
Backup point guard Shane Larkin, who could see an increased role if Irving is out Sunday, scored a team-high 16 points in Friday's win.
"We've been preaching next man up forever," Celtics guard Terry Rozier said. "Lately, our team is dropping like flies. You just gotta be ready. Shane did a great job, stepping up, coming in [Friday]. Like you said, you just never know in this league when your number is going to be called. We did a good job handling that."