Cowboys DE Marshawn Kneeland Diagnosed with Stage 1 CTE

Former Dallas Cowboys defensive end Marshawn Kneeland, who died by suicide last November, was posthumously diagnosed with Stage 1 chronic traumatic encephalopathy (CTE), researchers announced Tuesday. The diagnosis was made by the Boston University CTE Center after his family donated his brain for research.

Kneeland, 24, was found deceased from a self-inflicted gunshot wound in Frisco, Texas, in the early hours of November 3, 2025, following a brief police pursuit. Authorities had been attempting a welfare check earlier that evening after his girlfriend, Catalina Mancera, received a concerning text message from him. He had played 17 snaps for the Cowboys just two days prior to his death.

In a statement, his family and Mancera said that while the diagnosis does not change the tragedy of his passing, it provides important context about his struggles. They shared the information to help the public understand what athletes in high-contact sports may face, emphasizing a desire to remember Kneeland with compassion.

Dr. Ann McKee, director of the Boston University CTE Center, said she was not surprised by the finding, noting that her center has found the progressive brain disease in...