Cowboys defensive end Marshawn Kneeland posthumously diagnosed with CTE

Former Dallas Cowboys defensive end Marshawn Kneeland, who died in November, was posthumously diagnosed with Stage 1 chronic traumatic encephalopathy (CTE).

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The family of Kneeland, 24, had donated his brain for research, ESPN reported. Boston University’s CTE Center made the diagnosis, according to a news release from the Concussion and CTE Foundation.

There are four stages of CTE, with Stage 4 showing the most damage.

“Unfortunately, I was not surprised to find CTE in the brain of Mr. Kneeland, because we have found this progressive brain disease in nearly half of the athletes we’ve studied who have died before the age of 30,” Ann McKee, director of the Boston University CTE Center and chief of neuropathology for the VA Boston Healthcare System, said in a statement. “Thanks to the generosity of our brain donor families, we now better understand the earliest stages of CTE, and it is bringing us closer than ever to diagnosing it during life. My team and I are fully dedicated to finding effective treatments and a cure for CTE.”

[ Cowboys defensive end Marshawn Kneeland dead at 24 ]

Kneeland died by suicide on Nov. 6, 2025. Police in Frisco, Texas, said Kneeland was found dead from an apparent self-inflicted gunshot wound, The Associated Press reported.

He was discovered after evading officials in his vehicle and then running away from the scene of an accident.

Kneeland’s family, including his girlfriend, Catalina Mancera, issued a statement on Tuesday, ESPN reported.

“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. One Love.”

Kneeland, a native of Grand Rapids, Michigan, was the Cowboys’ second-round pick (56th overall) out of Western Michigan in the 2024 NFL draft.

In 18 games, he had 26 tackles and one sack.

Kneeland scored his first NFL touchdown three nights before his death, recovering a punt in the end zone during the Cowboys’ 27-17 loss to the Arizona Cardinals.

During his final year at Western Michigan, Kneeland had a career-high 57 tackles and 4.5 sacks. He was named to the second team in the Mid-American Conference.

In 38 college games, he had 27.5 tackles for loss, 13 sacks, three forced fumbles and three pass deflections.

Kneeland’s mother, Wendy Kneeland, died as the defensive end was preparing for the NFL draft.

Kneeland wore his mother’s ashes on a necklace after he was drafted.

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