Cowboys' Marshawn Kneeland Diagnosed With CTE After Death, Family Reveals Suicide Findings

Researchers said the diagnosis underscores growing evidence that repeated head impacts can cause CTE even in athletes playing under modern safety standards.

Rudy Blalock

Published: 7/7/2026, 10:24:07 PM EDT

Cowboys' Marshawn Kneeland Diagnosed With CTE After Death, Family Reveals Suicide Findings — Dallas Cowboys defensive end Marshawn Kneeland (94) walks off the field after a preseason NFL football game against the Baltimore Ravens in Arlington, Texas, on Aug. 16, 2025. (Richard W. Rodriguez/AP Photo)

Researchers have confirmed that Marshawn Kneeland, the Dallas Cowboys defensive end who died from a gunshot wound in November 2025, had the brain disease chronic traumatic encephalopathy (CTE) and died by suicide.

Scientists at the Boston University CTE Center diagnosed the 24-year-old with stage 1 CTE—the earliest of four stages—following a post-mortem analysis of his brain tissue, according to a press release issued Tuesday by the Concussion & CTE Foundation.

The findings, which also confirmed he had died by suicide, were released publicly by Kneeland's family.

"Unfortunately, I was not surprised to find CTE in the brain of Mr. Kneeland, because we have found this progressive brain disease in nearly half of the athletes we've studied who have died before the age of 30," said Dr. Ann McKee, director of the Boston University CTE Center and chief of neuropathology for the VA Boston Healthcare System.

"Thanks to the generosity of our brain donor families, we now better understand the earliest stages of CTE, and it is bringing us closer than ever to diagnosing it during life. My team and I are fully dedicated to finding effective treatments and a cure for CTE."

Kneeland began playing tackle football at age 7, according to the foundation. He went on to star at Western Michigan University before the Cowboys selected him in the second round of the 2024 NFL Draft, 56th overall. He was in his second season with Dallas when he died.

His death came in the early morning hours of Nov. 6, 2025, in Frisco, Texas. Texas Department of Public Safety troopers had attempted to pull over a vehicle the previous evening that evaded them and entered Frisco. The vehicle was later found crashed on southbound Dallas Parkway near Warren Parkway. The driver—later identified as Kneeland, a Plano, Texas, resident—fled on foot.

After a multi-agency search involving K-9 and drone units, officers received word that Kneeland had expressed suicidal ideations, according to the Frisco Police Department. He was found dead at 1:31 a.m. with what appeared to be a self-inflicted gunshot wound.

Just days before his death, Kneeland had recorded his first career NFL touchdown, recovering a blocked punt during a Monday Night Football matchup against the Arizona Cardinals.

In a statement at the time, the Cowboys confirmed his passing. "It is with extreme sadness that the Dallas Cowboys share that Marshawn Kneeland tragically passed away this morning," the team said. "Marshawn was a beloved teammate and member of our organization. Our thoughts and prayers regarding Marshawn are with his girlfriend Catalina and his family."

One week after Kneeland's death, Cowboys head coach Brian Schottenheimer disclosed during a press conference that Kneeland's girlfriend, Catalina Mancera, was pregnant with their child, and that the organization had established a memorial fund for her and the baby's long-term support. "We want to make sure she's taken care of, and the baby's taken care of for the rest of their lives," Schottenheimer said.

Kneeland had carried personal loss into his NFL career. His mother, Wendy, died unexpectedly on Feb. 18, 2024—just as he was preparing for the NFL scouting combine—and he wore a small urn containing her ashes on a chain around his neck throughout his career.

Modern Measures Fail

Dr. Chris Nowinski, CEO of the Concussion & CTE Foundation, stressed that modern safety measures have not eliminated the disease's risk.

"Mr. Kneeland played in the modern era of concussion protocols and better helmets, and yet he still developed CTE," Nowinski said. "We have no reason to believe the current generation is at a lower risk of CTE than previous generations. Concussion protocols do not prevent CTE, because CTE is caused by repeated head impacts, not just concussions. If we want to reduce CTE risk, we must implement CTE prevention protocols and aggressively reduce the number and strength of head impacts at every level of the game."

In a statement released through the foundation, Kneeland's family—including Mancera—said the diagnosis provides important context.

"While this diagnosis does not change the tragedy of his passing, it provides important context about some of the struggles he may have been facing," the family said. "We share this information to help people understand what NFL and other high contact sport athletes might be struggling with. Raising awareness is important to us. We continue to remember Marshawn with compassion for the person he was, rather than defining him by the final moments of his life. One Love."

The family is not granting interviews at this time and has asked for privacy.

Note: Suicide is complex and multifactorial. A post-mortem CTE diagnosis should not be considered the cause of a suicide and is not known to be a risk factor for suicide. If you or someone you know is struggling, the 988 Suicide & Crisis Lifeline is available 24/7 by calling or texting 988. For CTE-related support, visit ConcussionAndCTE.org/Helpline.