Hughes had suffered an injury in an August 1971 preseason game against the Buffalo Bills, which led to him collapsing in the locker room.

Hughes, who would suffer from what he believed was acid reflux and other maladies for the remaining two months of his life, insisted on continuing to play, saying that the pain he was experiencing was "not that bad.

Late in the fourth quarter, with Detroit trailing 28–23, the Lions were driving into Chicago territory and Hughes, who entered the game as an injury replacement, caught a pass from quarterback Greg Landry for 32 yards and a first down at the Bears' 37-yard line.

The game was played to its conclusion in front of a now-stunned silent crowd in Tiger Stadium, with the Bears' lead holding.

A postmortem examination revealed that Hughes was suffering from undiagnosed and advanced arteriosclerosis (one of his coronary arteries was 75% blocked) and that he had a family history of heart disease.

[9][10] Hughes was buried in San Antonio, Texas, and all 40 of his Lions teammates attended his funeral, including head coach Joe Schmidt.