Former Dallas Cowboys player Marshawn Kneeland had stage 1 CTE when he died, researchers confirmed.
A heartbreaking new medical update has shed light on the final months of former Dallas Cowboys defensive end Marshawn Kneeland. On Tuesday, July 7, 2026, scientists announced that the 24-year-old football player was suffering from Stage 1 chronic traumatic encephalopathy (CTE), a progressive and degenerative brain disease caused by repeated hits to the head, when he tragically died by suicide last year.
The medical diagnosis was made public by researchers at Boston University’s CTE Center. Because CTE cannot be detected during a person’s life, doctors had to perform a postmortem analysis of Kneeland’s brain tissue after his family generously donated it for scientific study. Stage 1 is categorized as the mildest of the four levels of the disease, often bringing on warning signs like severe headaches, depression, mood swings, and a noticeable loss of concentration.
Dr. Ann McKee, the director of the BU CTE Center, explained that finding the disease in someone so young is devastating but no longer unexpected. Her team has discovered early-stage CTE in nearly half of all the contact-sport athletes they have examined who died before turning 30 years old. Medical experts and advocates point out that Kneeland’s diagnosis proves that modern safety equipment and updated concussion protocols are still not doing enough to protect players. Dr. Chris Nowinski, the CEO of the Concussion & CTE Foundation, stressed that CTE is triggered by the routine, repeated head impacts built into the sport itself, meaning the current generation of players remains at severe risk.
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The tragic events leading to this discovery unfolded on November 6, 2025, in Frisco, Texas. State troopers attempted to pull Kneeland over for a routine traffic violation, which triggered a high-speed car chase. After crashing his vehicle, Kneeland fled into the night on foot. Police later stated that as they searched the area, friends of the athlete reported receiving a group text message from him saying goodbye. He was found dead a short time later from a self-inflicted gunshot wound.
Kneeland’s football journey began when he was just 7 years old playing tackle football. He grew up to become a standout star for Western Michigan University before the Dallas Cowboys selected him in the second round of the 2024 NFL Draft. He played 18 games for the franchise across two seasons, even scoring his first career touchdown just three days before his passing.
In an emotional statement, Kneeland’s family and his girlfriend, Catalina Mancera, who recently gave birth to their son, expressed that while the brain diagnosis does not change the pain of their loss, it offers critical context regarding the invisible mental health battles he was facing. The family emphasized that they chose to share this deeply personal information to raise public awareness and help people understand the silent structural damage that high-contact athletes might be carrying. They urged the public to remember Marshawn for his compassion and the person he was, rather than defining his legacy by the final, difficult moments of his life.
