Artest didn't travel with the Lakers to Saturday's game at Sacramento after tripping over a box and falling down a flight of stairs at his home on Christmas night, the team said in a news release.
He was treated at UCLA Medical Center, undergoing a CT scan and receiving stitches in the back of his head and his elbow. A neurologist examined him on Saturday and confirmed he had a concussion, the team said. Artest is day to day.
Artest scored 13 points and fouled out while guarding LeBron James in the Lakers' 102-87 loss to Cleveland earlier Friday. Artest is averaging 12.3 points and 4.8 rebounds in his first season with Los Angeles after signing as a free agent.
Lakers coach Phil Jackson allowed his players to stay home with their families on Christmas night, apparently getting permission from the NBA to fly to Sacramento on Saturday morning.
Asked his interpretation of Artest's injury before the Lakers' 112-103 win against the Kings in double overtime, Jackson responded, "What do you mean, 'What's my interpretation?' What's that supposed to mean?
"Let me see, my interpretation is that an accident happened, he fell down, he ended up in the hospital, and he came out with some stitches. Other than that, I can't add anything to it."
Los Angeles began a stretch with four games in five days on Christmas, culminating in a home game against Golden State on Tuesday.
"What I was telling the team is that he brings a certain physical presence to our game," Jackson said. "And we'll miss that part of his game."