Cowboys’ Marshawn Kneeland Had CTE at Time of Suicide, Researchers Confirm

Eight months after his death, the family of former Dallas Cowboys defensive end Marshawn Kneeland has confirmed what many feared. Researchers at Boston University’s CTE Center found that Kneeland had Stage 1 chronic traumatic encephalopathy, the mildest form of the degenerative brain disease linked to repeated head hits.

Kneeland died by suicide in November 2025 at age 24. His family donated his brain for study, and the results came back this week.

His girlfriend, Catalina Mancera, 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,” she said. “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.”

Boston University’s CTE Center was careful to note that a posthumous CTE diagnosis should not automatically be considered the cause of a suicide. They described suicide as “complex and multifactorial.” But the diagnosis adds a layer of understanding to Kneeland’s final days.

Red flags that went back years

According to ESPN, concerns about Kneeland’s mental health dated to his college days at Western Michigan in 2020. His girlfriend said at the time of his death that he had been struggling. Kneeland allegedly told her he would “end it all” before he died.

On the night of November 5, 2025, Kneeland fled the scene of a car accident on foot after evading police. He was found dead the next morning. The Frisco Police Department investigated his death as a suicide.

Kneeland was a second-round pick by the Cowboys in 2024. In his two NFL seasons, he played 26 games and started 18. He recorded 26 total tackles, one fumble recovery, and no sacks. His death shook the organization and raised broader questions about player safety and mental health support in the league.

The NFL has faced repeated scrutiny over CTE and brain trauma. The league has changed concussion protocols and funded research, but critics say it hasn’t done enough. Kneeland’s case is another painful reminder that the problem isn’t going away.

His family now hopes the diagnosis will help others. As Mancera put it: raising awareness is the goal. Nothing will bring Marshawn back. But maybe his story can change how teams treat players who are hurting.