Ken Stabler has been diagnosed with brain disease CTE.

Stabler, who died of colon cancer at 69 in July, had Stage 3 chronic traumatic encephalopathy, Dr. Ann McKee told The Associated Press. McKee said the disease was widespread throughout his brain, with "quite severe" damage to the regions involving learning, memory and regulation of emotion.

"We've now found CTE in former NFL players who played every position except kicker," said McKee, a professor of neurology at Boston University. "While we know on average that certain positions experience more repetitive head impacts and are more likely at greater risk for CTE, no position is immune."

The disease, which can only be diagnosed after death, is linked to repeated brain trauma and associated with symptoms such as memory loss, depression and progressive dementia.