Marshawn Kneeland Diagnosed with Stage 1 CTE

Tragic Loss and Family’s Decision to Share Brain Research

Marshawn Kneeland, a 24‑year‑old defensive lineman for the Cowboys, died by suicide in November 2025. His family authorized a post‑mortem brain analysis through the Concussion & CTE Foundation. The examination uncovered a stage 1 diagnosis of chronic traumatic encephalopathy, the earliest level on a four‑point scale.

Stage 1 marks the lowest severity, indicating the disease has begun to develop but remains less advanced than later stages. Dr. Ann McKee, director of the Boston University CTE Center, noted she was “not surprised” after finding CTE in Kneeland’s brain. She explained that researchers have observed this progressive condition in nearly half of the athletes who died before age 30 in their studies.

The findings also highlight a shift toward earlier detection. McKee’s team says the data brings them “closer than ever to diagnosing it during life,” and they remain committed to seeking effective treatments and a cure. Despite advances, CTE can only be confirmed by examining brain tissue after death.

What Current Safety Measures Miss

Chris Nowinski, CEO of the Concussion & CTE Foundation, emphasized that modern concussion protocols and improved helmets have not insulated players from CTE. He stated that Kneeland “played in the modern era… and yet he still developed CTE.” Nowinski warned that repeated head impacts—not just diagnosed concussions—drive the disease. He called for dedicated CTE prevention protocols and aggressive reductions in the number and force of head blows at every level of sport.

The reality extends beyond American football. Soccer players regularly head the ball, generating powerful impacts that can accumulate over time. Hockey, rugby, boxing, and other combat sports also expose participants to frequent head strikes. Even basketball athletes suffer sub‑concussive blows that, while less severe, still affect the brain.

Balancing Risk and Reward in High‑Contact Sports

NFL players often accept the dangers as part of the game, but awareness of long‑term health issues is growing. Athletes at all levels must understand that participation carries risks of immediate injuries and chronic conditions such as ALS, Alzheimer’s, and Parkinson’s disease, in addition to CTE. Kneeland’s girlfriend, Catalina Mancera, offered perspective: “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’s decision to release the brain‑analysis results aims to raise awareness about hidden struggles many elite athletes face. They emphasized compassion over defining Marshawn by his final moments. Their openness underscores a broader push for transparency in how sports organizations address head‑impact safety.

Ultimately, most participants weigh the benefits of competition against the potential long‑term consequences. Informed consent now includes a fuller picture of risks, empowering athletes to make choices that align with their health priorities.