Point guard Derrick Rose requires surgery for a torn meniscus in his right knee and will be out indefinitely, the Chicago Bulls announced Saturday.
Rose left Friday night's game in Portland after the knee buckled while he was cutting in the third quarter. He left the arena on crutches.
An MRI on Saturday in Los Angeles revealed a medial meniscus tear, the team said.
Rose sat out the 2012-13 season with a torn left ACL suffered in April 2012.
The 2011 NBA Most Valuable Player is averaging 15.4 points and four assists per game and shooting 36 percent from the field this season.
"It's a huge loss," guard Kirk Hinrich told the Chicago Tribune. "Everything we do is built around him. Losing one of the best players in the league obviously changes the landscape of things. I just feel bad for him personally."
Coach Tom Thibodeau said, "I know how much work he has put into his rehab and the type of person and player he is. So I feel for him because of all the things that he does and what they mean to our team."
Forward Luol Deng added, "Guys have just got to pick it up. Obviously, it'll be a setback not having him. But we've been there before. We've just got to play together."