Marshawn Kneeland, a 24-year-old Dallas Cowboys defensive end, was diagnosed with Stage 1 chronic traumatic encephalopathy (CTE) after his death by suicide in November 2025. The findings were released by his family through the Concussion & CTE Foundation, with analysis conducted by the Boston University CTE Center.
Kneeland’s family emphasized awareness in a statement, noting the diagnosis provides context for his struggles. They urged understanding of the challenges faced by athletes in high-contact sports. The family also expressed compassion for Kneeland, remembering him beyond the circumstances of his death.
Police reported Kneeland died after a high-speed chase following a traffic violation. He was found with a self-inflicted gunshot wound, and dispatch audio revealed he had sent a group text saying goodbye to his family.
CTE is a degenerative brain disease linked to repetitive head trauma and can only be diagnosed posthumously. Dr. Ann McKee, director of the Boston University CTE Center, stated that nearly half of athletes studied before age 30 showed signs of the disease. Kneeland began playing tackle football at age 7.
The family’s decision to share the findings aims to raise awareness about the risks of CTE in contact sports, particularly for young athletes.