The family of former Dallas Cowboys defensive end Marshawn Kneeland announced Tuesday that he had early-stage chronic traumatic encephalopathy (CTE), a degenerative brain disease linked to repetitive head trauma.
The Boston University CTE Center conducted the post-mortem analysis of the 24-year-old's brain and determined he was in stage one of the four stages of CTE.
Kneeland died by suicide in November 2025 in Austin, Texas, following a high-speed police pursuit that began over a traffic violation.
According to authorities, Kneeland fled a vehicle crash on foot after evading Texas Department of Public Safety troopers.
While searching for him, officers learned from a dispatcher that acquaintances had received a group text message from Kneeland saying goodbye.
The progressive brain disease can only be diagnosed after death and is known to trigger depression, impulsive behavior, and violent mood swings in contact sport athletes and combat veterans.
Kneeland's family, including his girlfriend Catalina Mancera, released a statement through the Concussion and CTE Foundation regarding the findings.
"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.
We share this information to help people understand what NFL and other high contact sport athletes might be struggling with," stated the family.
The family expressed their desire to promote understanding of the challenges faced by contact sport athletes who endure repeated impacts.
"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," the family added.
A 2021 study by Harvard Medical School and the Boston University CTE Center indicated that former NFL players face a risk of developing ALS that is more than four times higher than the average male population.
Kneeland began playing tackle football at age 7 and played for Western Michigan University before being selected in the second round of the 2024 NFL draft.
Dr. Chris Nowinski, CEO of the Concussion & CTE Foundation, noted that the diagnosis occurred despite modern safety equipment and concussion protocols.
"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," said Dr. Chris Nowinski.
Nowinski emphasized that current measures fail to eliminate the underlying cause of the condition.
"If we want to reduce CTE risk, we must implement CTE prevention protocols and aggressively reduce the number and strength of head impacts at every level of the game," Nowinski stated.
