Former Cowboys player posthumously diagnosed with Stage 1 CTE

Former Cowboys defensive end Marshawn Kneeland was posthumously diagnosed with Stage 1 chronic traumatic encephalopathy. Kneeland died by suicide in November 2025 at the age of 24. Boston University's CTE Center made the diagnosis after his family donated his brain for research. There are four stages of CTE, with Stage 4 showing the most damage.

Kneeland's family, including his girlfriend, released a statement Tuesday. "While this diagnosis does not change the tragedy of his passing, it provides important context about some of the struggles he may have been facing," the statement read. "We share this information to help people understand what NFL and other high contact sport athletes might be struggling with.

Raising awareness is important to us. We continue to remember Marshawn with compassion for the person he was, rather than defining him by the final moments of his life. In one incident, he was required to turn in his firearm to police until cleared by a counselor.

In another, a friend called authorities with concern over his well-being. He was found on railroad tracks, saying he hoped a train would run him over.

Texas police found Kneeland's body in the early morning of Nov. 6, 2025, after he evaded officers during a traffic pursuit, crashed his car and fled on foot. A report released Friday by the Texas Department of Public Safety said a trooper saw the car speeding, sometimes exceeding 145 mph, and making several unsafe lane changes.

"We have found this progressive brain disease in nearly half of the athletes we've studied who have died before the age of 30," she said.