In November 2025, Cowboys player Marshawn Kneeland died. It has now been revealed that the 24-year-old suffered from CTE.

Last November, Marshawn Kneeland, an edge rusher for the Dallas Cowboys, took his own life at the age of just 24. The athlete had taken his own life with a firearm.

It has now been revealed that Kneeland suffered from chronic traumatic encephalopathy, better known as CTE. The disease was in stage one. This information comes from a statement issued by his family and the Concussion & CTE Foundation.

Researchers at Boston University’s CTE Center had examined the NFL player’s brain postmortem and made the diagnosis.

“Unfortunately, I was not surprised to find CTE in Mr. Kneeland’s brain, as we have identified this progressive brain disease in nearly half of the athletes we have examined who died before the age of 30,” said Dr. Ann McKnee, director of the center, in the statement.

No Better Protection Against CTE

“Thanks to the generosity of our brain donors’ families, we now have a better understanding of the earliest stages of CTE, bringing us closer than ever to a diagnosis during a person’s lifetime. My team and I are fully committed to finding effective treatments and a cure for CTE.”

CTE is a degenerative brain disease that destroys nerve cells and is associated with repeated traumatic brain injuries—including concussions.

Currently, the diagnosis can only be made after a person’s death. It has frequently been diagnosed in American football players, boxers, and war veterans.

“Mr. Kneeland played at a time when there were already concussion protocols and better helmets, and yet he still developed CTE,” said Chris Nowinski, CEO of the Concussion & CTE Foundation.

Kneeland expressed suicidal thoughts

“We have no reason to believe that current players are at a lower risk of CTE than previous generations. Concussion protocols do not prevent CTE, as CTE is caused by repeated blows to the head and not just by concussions.”

He continued: “If we want to reduce the risk, we must implement preventive measures and consistently reduce the number and severity of head impacts at all levels of the sport.”

Kneeland had been involved in a police chase last November after committing a traffic violation. After his car crashed, he fled the scene of the accident.

A few hours later, officers found him shot to death.  During the search, they received information that Kneeland had “expressed suicidal intentions.”