Postmortem Analysis Diagnoses Former Dallas Cowboys Player Marshawn Kneeland With Stage 1 CTE

Kneeland died by suicide after a police chase in which authorities attempted to pull over his car; he crashed, fled on foot, and was later found dead.
Kneeland’s girlfriend, Catalina Mancera, was pregnant at the time of his death and later gave birth to their son last month, a detail the family shared to provide context about his life and struggles.
A 2023 JAMA study cited by BU researchers found CTE in a substantial portion of young athletes who died before age 30: 41.4% (63 of 152 brains), with most cases mild (stages I/II) and a few at stage III, spanning NFL players, college athletes, and rugby players.
Kneeland was a Grand Rapids native and Western Michigan standout who entered the NFL as a Cowboys second-round pick in 2024 and appeared in 18 games over two seasons.
Marshawn Kneeland, a 24-year-old former Dallas Cowboys defensive end, has been posthumously diagnosed with stage 1 chronic traumatic encephalopathy — the earliest and mildest form of the degenerative brain disease, according to Detroit News and WGN Radio. The findings were released by Boston University's CTE Center and the Concussion & CTE Foundation following Kneeland's death by suicide in November 2025.
Kneeland played just 18 NFL games across two seasons after being selected by Dallas in the second round of the 2024 draft. His death followed a police chase in which authorities attempted to pull over his car. He crashed, fled on foot, and was later found dead, WGN Radio reported.
CTE is a brain disease linked to repeated head impacts. It can only be diagnosed after death, through examination of brain tissue. Stage 1 is the mildest form — it does not mean a person was severely ill. But experts say it is still meaningful, especially in someone as young as Kneeland, The Alpena News noted.
Boston University researchers pointed to a 2023 study published in JAMA that found CTE in 41.4% of young athletes who died before age 30 — that is 63 out of 152 brains examined. Most cases were mild, at stages I or II. The group included NFL players, college athletes, and rugby players. Experts stress that CTE is not proven to have caused Kneeland's death.
Kneeland's family released the brain analysis results themselves. In their statement, they said the diagnosis helps explain struggles he faced but should not define his life or his death. They asked the public to see the full picture of who he was, Detroit News reported.
The family also shared that Kneeland's girlfriend, Catalina Mancera, was pregnant at the time of his death. She has since given birth to their son. The family included this detail to give context about the pressures and circumstances surrounding his final months, according to MyArkLaMiss.
Kneeland grew up in Grand Rapids, Michigan, and became a standout at Western Michigan University. The Cowboys selected him in the second round of the 2024 NFL Draft. He appeared in 18 games over two seasons — a brief career that still exposed him to the repeated hits that researchers link to CTE, Detroit News reported.
His case highlights a troubling reality. Modern helmets and concussion protocols have improved. But they have not fully stopped early-stage CTE from developing in some young players. Kneeland was just 24. The JAMA study BU cited shows he is far from alone — nearly half of athletes who die young show signs of the disease, The Alpena News noted.
Researchers are careful not to draw a straight line between stage 1 CTE and suicide. The Concussion & CTE Foundation stressed that the disease was present but that many factors shape mental health outcomes. CTE alone is not a death sentence, and its link to suicidality is still being studied, according to WGN Radio.
Still, Kneeland's diagnosis adds to a growing body of evidence that even short NFL careers carry real neurological risk. Nearly half of young athletes who die before 30 show CTE signs at autopsy, the JAMA data shows. Experts say the conversation must be nuanced — acknowledging the risk without overstating what a stage 1 finding means for any individual, MyArkLaMiss reported.
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