Former Cowboys Player Posthumously Diagnosed with CTE After Death
Former Cowboys player posthumously diagnosed with CTE; condition linked to repeated head trauma and behavioral changes.
Event / Health
NFL Player CTE Health Crisis
Former Dallas Cowboys defensive end Marshawn Kneeland died by suicide in November 2025. Posthumous brain analysis diagnosed him with Stage 1 chronic traumatic encephalopathy (CTE), a degenerative disease linked to repeated head impacts from tackle football beginning at age 7. The case highlights ongoing concerns about long-term neurological effects in contact sport athletes despite modern safety protocols.
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2026-08-16 to 2026-11-13 · UTC publication dates
Coverage begins 8 Jul, 04:22 UTC
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What happened
Marshawn Kneeland posthumously diagnosed with Stage 1 chronic traumatic encephalopathy
The Boston University CTE Center analyzed Marshawn Kneeland's brain tissue after his death and diagnosed him with Stage 1 of chronic traumatic encephalopathy (CTE), one of four stages of the degenerative brain disease. Dr. Ann McKee, director of the Boston University CTE Center, stated she was not surprised by the diagnosis, noting that CTE has been found in nearly half of the athletes studied who died before age 30. Kneeland's family released the results through the Concussion & CTE Foundation.
NFL players more than four times more likely to develop ALS than other men
According to a 2021 study by Harvard Medical School and the Boston University CTE Center, NFL players are more than four times more likely to develop amyotrophic lateral sclerosis (ALS) than other men, indicating a connection between football-related head trauma and neurological disease.
Kneeland developed CTE despite modern concussion protocols and improved safety equipment
Marshawn Kneeland developed Stage 1 CTE despite playing in the modern era of professional football with concussion protocols and improved helmet technology. Dr. Chris Nowinski, CEO of the Concussion & CTE Foundation, stated that concussion protocols do not prevent CTE because the disease is caused by repeated head impacts, not solely by concussions. Nowinski emphasized that there is no evidence the current generation has lower CTE risk than previous generations.
Former Dallas Cowboys defensive end Marshawn Kneeland died by suicide in November 2025
Marshawn Kneeland, a 24-year-old former Dallas Cowboys defensive end, died by suicide in November 2025 following a high-speed chase with police. After failing to stop for a traffic violation, Kneeland fled the resulting vehicle crash on foot. While authorities were searching for him, a dispatcher reported that people who knew him had received a group text from Kneeland saying goodbye, indicating suicidal intent. He died by shooting himself.
CTE linked to repeated head trauma and behavioral symptoms including violent mood swings and depression
Chronic traumatic encephalopathy (CTE) is a degenerative brain disease found in athletes in contact sports, combat veterans, and others who experience repetitive head trauma. The disease has been documented to cause violent mood swings, impulsive behavior, and depression. CTE can only be diagnosed after death through brain tissue analysis. The condition has been identified in athletes across multiple sports including football, hockey, and soccer.
Marshawn Kneeland began playing tackle football at age 7
Marshawn Kneeland began playing tackle football at age 7. He continued playing through high school and college, attending Western Michigan University before being selected by the Dallas Cowboys in the second round of the 2024 NFL draft.
Kneeland drafted by Dallas Cowboys in second round of 2024 NFL draft
Marshawn Kneeland was selected by the Dallas Cowboys in the second round of the 2024 NFL draft. He recorded 26 tackles and one sack in 18 career games with the Cowboys. His first NFL touchdown came just days before his death, when he recovered a blocked punt in the end zone against the Arizona Cardinals.
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