The Cleveland Cavaliers announced Irving would be out approximately 45 minutes before tipoff on Sunday.
Irving was evaluated by team medical personnel before the game and the determination was made to hold him out, according to the Cavs. His status for Tuesday's Game 4 remains questionable, the team said.
Irving arrived to Quicken Loans Arena more than 3 hours early Sunday and underwent an intense 50-minute workout with player development coach Phil Handy involving a variety of shooting, ballhandling and full-court running drills.
However, the fourth-year veteran did not participate in the team portion of Cavs shootaround Sunday morning, a league source told ESPN.com. He opted for some light personal work with Handy in the morning.
Irving aggravated his left knee in the third quarter of Game 1, causing him to miss Friday's Game 2 after traveling with Cavs team physician Dr. Richard Parker to be examined by Dr. James Andrews in Pensacola, Florida. Matthew Dellavedova started in Irving's place in Game 2, contributing 11 points, six rebounds and four steals in Cleveland's 94-82 victory.
LeBron James wore a microphone during the TNT telecast Friday and was recorded saying to Irving, "I told you I got your back, G," after the game. James said after practice Saturday that Irving believed it would have been detrimental to the Cavs' success had he played in Game 2.
"Obviously, he didn't feel like what he was going to be able to do was going to help the team. He felt like he was going to hurt the team," James said. "That's the only reason he would sit out, he felt like he was going to hurt the team. So I told him before the game, 'That's why we're a team. That's why it's next man up, and that's what I'm here for. I got your back and whatever decision that you decide to make, know that we're ready for you whenever you decide to come back, whenever you're ready physically and mentally to come back.' That's what it was about."