Dallas Cowboys Player Marshawn Kneeland Diagnosed with Brain Disease After Death

Marshawn Kneeland, a defensive lineman for the Dallas Cowboys who died by suicide in November at age 24, has been diagnosed with stage 1 chronic traumatic encephalopathy (CTE), according to postmortem analysis conducted by Boston University's CTE Center. The diagnosis provides a medical framework for understanding neurological struggles the athlete may have faced, though researchers emphasize CTE cannot be identified during life and can only be confirmed through brain tissue examination after death.

The Diagnosis and Its Implications

Dr. Ann McKee, director of Boston University's CTE Center, conducted the brain tissue analysis that revealed the presence of stage 1 CTE in Kneeland's brain. Of the athletes studied by the center who died before age 30, nearly half displayed evidence of the progressive brain disease. Stage 1 represents the mildest category of four CTE severity levels, typically associated with headaches, concentration difficulties, short-term memory problems, depression, and executive function challenges.

Kneeland began playing tackle football at age 7 and competed for Western Michigan University before being selected in the second round by the Dallas Cowboys in 2024. He appeared in 18 games for the team, including four starts as a defensive end, and recorded his first career touchdown during a November loss to the Arizona Cardinals.

Understanding CTE and Its Progression

Chronic traumatic encephalopathy develops as a result of repeated head trauma common in contact sports including American football, rugby, and boxing. In its initial stages, the disease causes cognitive and behavioral symptoms; as it advances, individuals may experience mood instability, suicidal ideation, severe memory loss, and dementia. The condition has been documented in dozens of former NFL players and remains a significant concern for professional athletes in high-impact sports.

Kneeland's family released a statement emphasizing that while the CTE diagnosis does not alter the tragedy of his passing, it provides essential context regarding his mental health struggles. They chose to share the findings to increase public awareness of the neurological challenges that NFL and other contact sport athletes may encounter throughout their careers and lives.