Bulls guard Derrick Rose suffered a medial meniscus tear to his right knee, which will require surgery, the team announced Saturday.
Rose injured his knee against the Trail Blazers on Friday night.
Subsequent examinations and an MRI confirmed the tear. Rose is out indefinitely.
The Chicago Tribune first reported the diagnosis.
The Bulls have not announced a timeline for Rose's recovery or return. The diagnosis is considered to be a less serious injury than the ACL tear he suffered during the 2012 playoffs that forced him to sit out the entire 2012-13 season.