The family of former Dallas Cowboys defensive end Marshawn Kneeland announced Tuesday that the 24-year-old had early-stage chronic traumatic encephalopathy (CTE) at the time of his death. Following Kneeland's suicide in November 2025, which occurred after a high-speed police chase and a vehicle crash, the Boston University CTE Center analyzed his brain tissue. Researchers determined he was in stage one of four of the degenerative brain disease. Kneeland, a former Western Michigan University player drafted in 2024, had played tackle football since age seven. His family released the findings through the Concussion and CTE Foundation to raise awareness regarding the struggles faced by contact sport athletes. Experts noted that current concussion protocols may not prevent CTE, as the disease is caused by repeated head impacts rather than just diagnosed concussions.