Tyler Sash was known for being a physical, playmaking safety. It’s what made him a fan favorite in Iowa City.

But Sash’s physical style took its toll.

In September, the former Hawkeye was found dead in his apartment at 27 after overdosing on painkillers. It was revealed that Sash was diagnosed with five concussions during his football career.

According to the New York Times, doctors concluded that he had chronic traumatic encephalopathy (CTE), which is a degenerative brain disease caused by repeated trauma that has been found in dozens of former NFL players.

Representatives from Boston University and the Concussion Legacy Foundation confirmed the findings to the New York Times. The doctor who conducted the study reportedly likened Sash’s brain to that of NFL Hall of Fame linebacker Junior Seau, who committed suicide.

Sash’s overdose was a result of mixing prescription drugs methadone and hydrocodone. He exhibited unusual behavior following his concussion-related retirement from the NFL.

Upon returning to his hometown of Oskaloosa, Sash led police on a four-block chase while operating a motorized scooter and was arrested for public intoxication. According to the New York Times, Sash struggled to retain a job because he couldn’t maintain his focus long enough to accomplish a task.

Sash was suspended from the NFL for testing positive for Adderall, which is commonly used to treat attention deficit hyperactivity disorder (ADHD).

The Hawkeyes honored Sash following his death by putting his No. 9 on the side of their helmets for the Iowa State game.