Marshawn Kneeland Found to Have CTE Following November 2025 Death

The medical findings surrounding Dallas Cowboys defensive end Marshawn Kneeland's death have now come to light. Eight months after the 24-year-old's passing in November 2025, researchers at Boston University's CTE Center have confirmed he was living with Stage 1 chronic traumatic encephalopathy.

Chronic traumatic encephalopathy, a progressive brain condition linked to repeated head trauma in contact sports, can only be definitively identified through post-mortem examination. The condition gained widespread public attention following the 2015 film "Concussion," which starred Will Smith.

Dr. Ann McKee, director of the Boston University CTE Center and chief of neuropathology for the VA Boston Healthcare System, reflected on the diagnosis: "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."

The finding carries particular significance given modern safety advancements in the sport. According to Dr. Chris Nowinski, CEO of the Concussion & CTE Foundation, "Mr. Kneeland played in the modern era of concussion protocols and better helmets, and yet he still developed CTE."

Kneeland's cause of death was officially determined to be suicide.