Researchers have determined that Dallas Cowboys defensive end Marshawn Kneeland suffered from Stage 1 chronic traumatic encephalopathy (CTE) and died by suicide, according to an announcement made on Tuesday, July 7. The Concussion & CTE Foundation released the findings eight months after the 24-year-old player died on November 5.
A post-mortem analysis of brain tissue conducted by the Boston University CTE Center confirmed the diagnosis. Dr. Ann McKee, director of the center, noted that the progressive brain disease was found in nearly half of the athletes they studied who died before age 30. Dr. Chris Nowinski, CEO of the Concussion & CTE Foundation, stated that Kneeland developed the condition despite playing in an era with improved concussion protocols and helmet technology.
Kneeland’s death was initially reported following a police pursuit on the evening of November 5. North Texas authorities stated that troopers attempted to stop him for a traffic violation on the northbound lanes of the Dallas North Tollway near Keller Springs Blvd. Kneeland refused to comply, leading to a chase that ended approximately three hours later. Frisco Police Department and Texas DPS aircraft located him near his crashed vehicle in the southbound lanes of the Dallas Parkway near Warren Parkway in Frisco at 10:39 p.m. Authorities determined he died from a self-inflicted gunshot wound.
The Concussion & CTE Foundation shared a statement from Kneeland’s family, which included his girlfriend, Catalina Mancera. The family noted that while the diagnosis does not alter the tragedy, it offers context for struggles he may have faced. They emphasized the importance of raising awareness for athletes in high-contact sports and asked that he be remembered with compassion rather than defined by the final moments of his life.
Kneeland had been a second-year player for the Cowboys. He died just days after recovering a blocked punt and scoring a touchdown in a game against the Arizona Cardinals. His mother, Wendy Kneeland, passed away unexpectedly in February 2024, shortly before he was selected in the second round of the 2024 NFL Draft. Following her death, he wore a necklace containing her ashes as a tribute.
