Late Dallas Cowboys' Marshawn Kneeland Diagnosed With CTE

Late Dallas Cowboys’ Marshawn Kneeland Diagnosed With CTE

Boston University researchers found former Dallas Cowboys pass rusher Marshawn Kneeland had Stage 1 CTE following a posthumous brain examination.

Dallas Cowboys v Las Vegas Raiders — Source: Candice Ward / Getty

November 2025, Dallas Cowboys pass rusher Marshawn Kneeland took his own life with a self-inflicted gunshot. According to doctors, 24 year old kneeland was diagnosed with CTE.

After his tragic death, his brain was sent to the center for posthumous examination. On Tuesday, doctors at Boston University’s CTE Center released their findings, saying that Kneeland had stage 1 CTE.

According to experts, the first stage, stage one of the disease, is characterized by short-term memory loss, mild aggression and depression, and headaches.

Baylor CTE Center doctor Dr. Anne McKee said: “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.”

Kneeland played only 18 NFL games over 2 seasons but has played tackle football since he was 7 years old.

Marshawn’s girlfriend Catalina Mancera said, “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 findings also show that despite an increased effort on player safety, football is still a very violent game.

Concussion & CTE Foundation CEO Chris Nowinski said, “Mr. Kneeland played in the modern era of concussion protocols and better helmets, and yet he still developed CTE. We have no reason to believe the current generation is at a lower risk of CTE than previous generations. Concussion protocols do not prevent CTE, because CTE is caused by repeated head impacts, not just concussions.”

Following his tragic death in November 2025 kneeland was mourned by friends, family, and fans, teammates, and coaches around the league and was described as a beloved teammate by Cowboys head coach Brian Schottenheimer as he fought back tears.

If you or someone you know is struggling or in crisis, help is available. Call or text 988 or chat 988lifeline.org.