Marshawn Kneeland, Late Dallas Cowboys Star, Had CTE at Time of Suicide
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Back in November of 2025, Dallas Cowboys defensive end Marshawn Kneeland died by suicide.
At the time, there was widespread speculation that Kneeland had been suffering from CTE, a condition tragically common among NFL players.
Now, those fears have been confirmed.


Eight months after Kneeland’s death at the age of 24, researchers have confirmed that Kneeland was suffering from Stage 1 chronic traumatic encephalopathy, a degenerative brain disease linked to repeated head impacts.
His family also confirmed that he died by suicide following the posthumous diagnosis.
The Concussion & CTE Foundation announced on July 7 that researchers at Boston University’s CTE Center examined Kneeland’s brain tissue after his death and identified early-stage CTE.
“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,” Dr. Ann McKee said in a statement.
McKee added that the findings underscore the need for continued research into the disease and its effects on young athletes.
Rather than allowing Kneeland’s story to end with tragedy, his loved ones hope his diagnosis encourages more conversations about the long-term effects of repetitive head trauma.
His girlfriend, Catalina Mancera, said the family chose to share the diagnosis publicly in the hopes that it could help others.
“Marshawn was so much more than the way he died,” she said. “If sharing his story helps even one family recognize the signs or pushes research one step further, then his life will continue to make a difference.”
Catalina welcomed a son by Marshawn in June, several months after Kneeland’s death.