Alex Karras was recently released from a California hospital after having kidney failure so he could spend his final days with family.
"He may be dying of kidney failure because now his body is catching up to the deterioration of his mind," Craig Mitnick, Karras' attorney in a lawsuit against the NFL, told the Associated Press on Tuesday afternoon.
The 77-year-old former defensive tackle and actor, who was born and raised in Gary, Ind., has been surrounded by his wife and kids at his home in Los Angeles.
In his day, Karras was one of the NFL's best defensive tackles. The Detroit Lions drafted Karras 10th overall in 1958 out of Iowa and he was a four-time All-Pro over 12 seasons with the franchise.
Karras became a bit of a celebrity through George Plimpton's behind-the-scenes book about what it was like to be an NFL player in the Motor City, Paper Lion: Confessions of a Second-string Quarterback. That led to Karras playing himself in the movie adaption, and it opened doors for him such as being an analyst alongside Howard Cosell and Frank Gifford on Monday Night Football.
Karras had a well-known appearance as Mongo in the 1974 movie Blazing Saddles and was a star in the 1980s sitcom Webster.
He took on another role this year as lead plaintiff in a complaint against the NFL by ex-players who claim the league didn't do enough to protect them from head injuries.
"Alex's decision to get involved in this was for the right reasons -- to help the game of football," Mitnick said.