Former Oakland Raiders quarterback Ken Stabler, who died in 2015 from complications resulting from colon cancer, also suffered from the effects of the degenerative disease chronic traumatic encephalopathy, the doctor who examined his brain told ESPN's Outside the Lines.
After his death on July 10 at the age of 69, Stabler's brain and spinal cord were donated to Boston University's Chronic Traumatic Encephalopathy Center to support research into degenerative brain disease among athletes. CTE, which is believed to be caused by repeated blows to the head, can only be diagnosed after death via an examination of brain tissue.