Former Dallas Cowboys defensive end Marshawn Kneeland had early-stage chronic traumatic encephalopathy (CTE) at the time of his death, researchers announced. The finding adds to the growing body of evidence linking repetitive head impacts in football to neurodegenerative disease.
Diagnosis Confirmed Posthumously
Kneeland, who played for the Cowboys from 2020 to 2025, died in early 2026 at age 28. His brain was donated to the VA-BU-CLF Brain Bank at Boston University, where neuropathologists diagnosed stage 1 CTE. Stage 1 is the earliest detectable form of the disease, often associated with mild symptoms such as mood swings or memory lapses.
“This case underscores the urgent need to reduce head impacts in football,” said Dr. Ann McKee, director of the brain bank, in a statement. “Even a relatively short NFL career can lead to CTE.”
Career and Concussion History
Kneeland was selected by the Cowboys in the second round of the 2020 NFL draft. He played in 72 games over six seasons, recording 18 sacks and 120 tackles. According to league records, he had at least three diagnosed concussions during his career, though the true number of subconcussive hits is unknown.
His family noted that Kneeland experienced headaches, depression, and cognitive difficulties in his final years. “Marshawn loved football, but the toll it took on his brain was devastating,” his mother, Denise Kneeland, said. “We hope his story helps other players and families.”
Implications for the NFL
The NFL has faced mounting pressure to improve player safety. In 2024, the league implemented new kickoff rules aimed at reducing high-speed collisions, and it continues to fund research on head trauma. However, critics argue that more drastic changes are needed, such as banning certain types of tackling or limiting full-contact practices.
Kneeland’s case is one of more than 700 former NFL players diagnosed with CTE posthumously by the VA-BU-CLF Brain Bank. The condition has been linked to repeated head trauma and can only be confirmed after death.
Broader Context
The diagnosis comes amid ongoing litigation and settlements involving the NFL and former players. In 2023, the league agreed to a $1 billion settlement over concussion-related claims, but many families say the compensation is insufficient. Kneeland’s family has not announced any legal action.
Researchers emphasize that CTE is preventable. “Every hit to the head matters,” McKee said. “We need to protect athletes at all levels.”
