Family Says Marshawn Kneeland’s CTE Diagnosis Provides Important Context While Raising Awareness About Brain Trauma in Contact Sport
The family of former Dallas Cowboys defensive end Marshawn Kneeland has revealed that he was diagnosed with early-stage chronic traumatic encephalopathy, or CTE, following his death in November 2025.
Researchers at the Boston University CTE Center diagnosed Kneeland with Stage 1 CTE, the earliest of the disease’s four stages, after examining his brain tissue following his death.
Kneeland was 24.
His family says the diagnosis does not explain away the circumstances surrounding his death but may provide important context about challenges he faced before he died.
“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 family said in a statement released through the Concussion & CTE Foundation. “We share this information to help people understand what NFL and other high contact sport athletes might be struggling with.”
Family Hopes Diagnosis Raises Awareness
Kneeland died by suicide in November 2025 following a high-speed police chase in North Texas.
CTE is a degenerative brain disease associated with exposure to repetitive head impacts. It has been found in athletes who played contact sports, military veterans and others with histories of repeated brain trauma.
The disease can currently be definitively diagnosed only after death.
Researchers have studied possible connections between CTE and symptoms that may include changes in mood, behavior and cognition. However, experts caution against treating a postmortem CTE finding as proof that the disease caused a person’s suicide. Suicide is complex, and the Concussion & CTE Foundation has specifically warned that a CTE diagnosis should not be viewed as the sole cause of a suicide.
Kneeland’s family, including his girlfriend, Catalina Mancera, said they chose to make the diagnosis public in hopes that his story could help families better understand the risks associated with repetitive head trauma.
“Raising awareness is important to us,” the family said. “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.”
Findings Renew Questions About Football and Brain Trauma
Kneeland’s diagnosis adds to years of research examining the neurological effects of repeated head impacts in football and other contact sports.
The Boston University CTE Center has studied donated brain tissue from former athletes and others exposed to repetitive head trauma as researchers work to better understand who develops the disease and why.
Kneeland had played tackle football from a young age before reaching the NFL. The Dallas Cowboys selected him in the second round of the 2024 NFL Draft after his college career at Western Michigan.
His death stunned the Cowboys organization and the broader NFL community. Players later wore tribute shirts honoring him before a November 2025 game against the Las Vegas Raiders.
For Kneeland’s family, releasing the CTE findings is part of a broader effort to ensure his life is remembered with compassion while drawing attention to questions that remain about brain trauma in high-contact sports.
Scientists are still working to determine why some people exposed to repeated head impacts develop CTE while others do not. Researchers are also studying potential methods to detect the disease during life and improve prevention and treatment of brain injuries.
For Kneeland’s loved ones, the diagnosis now provides another piece of a painful story and a reason to continue pushing for greater awareness.
