Marshawn Kneeland had early-stage CTE after his death, family says

Boston University CTE Center researchers diagnosed former Dallas Cowboys defensive end Marshawn Kneeland with Stage 1 chronic traumatic encephalopathy after examining brain tissue donated by his family. The finding, announced July 7, 2026, came about eight months after Kneeland died by suicide in November 2025 at age 24.

Stage 1 is the earliest of the four recognized stages of CTE, a progressive brain disease linked to repeated head trauma. Kneeland was in his second NFL season when he died, and his case adds another young professional player to the mounting record of football careers cut short by brain injury concerns.

Kneeland’s death followed a high-speed chase with police in North Texas. After his family donated his brain for post-mortem research, the Boston University team identified early-stage CTE, and the Concussion & CTE Foundation released the finding publicly.

The family said the diagnosis provided “important context” for understanding Kneeland’s death. That response reflects how CTE cases are increasingly shaping public discussion not only about player safety, but also about the long-term mental-health risks that can accompany repeated blows to the head.

Dr. Ann McKee, a Boston University researcher who leads much of the center’s CTE work, said she was not surprised to find the disease in Kneeland’s brain. The center has identified CTE in nearly half of the athletes it has studied who died before age 30, a grim pattern that continues to fuel scrutiny of football at every level.

Kneeland’s case also lands in the middle of the NFL’s broader concussion and CTE debate. For the league, each new diagnosis raises the same hard questions: how much damage accumulates before symptoms appear, how many players are at risk while still active, and whether current safeguards are enough to protect players and their families from a disease that can only be confirmed after death.