(Portland, OR) -- Officials say former Portland Trail Blazer great Jerome Kersey died after a blood clot traveled to his lungs. The Oregon State Medical Examiner's Office says the clot broke loose from Kersey's left calf and caused a pulmonary thromboembolism. Doctor Larry Lewman of the medical examiner's office says he's running tests to determine how long the clot may have been in Kersey's body. Kersey died Wednesday at Meridian Park Hospital in Tualatin.