Marshawn Kneeland, the former Dallas Cowboys defensive end who died by suicide in November following a high-speed police chase, was diagnosed posthumously with early-stage chronic traumatic encephalopathy (CTE), his family announced. The Boston University CTE Center conducted an analysis of Kneeland’s brain tissue after his death and identified evidence of the degenerative brain disease at stage one, the earliest of four stages.

CTE is a progressive neurological condition linked to repeated head injuries, frequently observed in contact sport athletes. Kneeland, who was 24 years old at the time of his death, began playing tackle football at age seven. He went on to play collegiate football at Western Michigan University before being selected by the Dallas Cowboys in the 2024 NFL Draft.

The diagnosis underscores growing concerns about the long-term health effects faced by professional football players and others exposed to repetitive brain trauma. Officials at the Boston University CTE Center have increasingly identified the disease in athletes across various levels of football, raising questions about prevention and safety measures within the sport.

Kneeland’s family expressed hope that this finding might contribute to broader awareness and research aimed at protecting athletes from similar outcomes.