Bears great Dick Butkus’ death certificate said he died of a stroke last month, per TMZ.

His occupation on the certificate was listed simply as “linebacker,” with his employer the NFL.

The Pro Football Hall of Fame linebacker died Oct. 5 at his home in Malibu, Calif., hours before the Bears began their “Thursday Night Football” game against the Commanders. They took the field for the following game wearing football-shaped patches with Butkus’ No. 51 on them.

Butkus was an eight-time Pro Bowl player and five-time all-pro during his nine-year career with the Bears from 1965-73. He would have turned 81 next month. 

“Dick was the ultimate Bear, and one of the greatest players in NFL history,” chairman George McCaskey said in a statement. “He was Chicago’s son. He exuded what our great city is about and, not coincidently, what George Halas looked for in a player: toughness, smarts, instincts, passion and leadership. He refused to accept anything less than the best from himself, or from his teammates.”