Sauer was a four-time All-Star in the American Football League. He played for the Jets in the A.F.L. and then the N.F.L. from 1965 through 1970, appearing in 84 games and catching 309 passes for 4,965 yards and 28 touchdowns.

He retired from the N.F.L. at the end of the 1970 season at 27, at the peak of his career (though he would return briefly to the game with short-lived rival leagues).

He had grown to hate the life of a pro football player, he said.

“When you get to the college and professional levels, the coaches still treat you as an adolescent,” he said in an interview in 1971 with the Institute for the Study of Sport and Society. “They know damn well that you were never given a chance to become responsible or self-disciplined. Even in the pros, you were told when to go to bed, when to turn your lights off, when to wake up, when to eat and what to eat. You even have to live and eat together like you were in a boys’ camp.”

Ten years later, he remained just as disillusioned. In an interview with The New York Times, he called professional football “a grotesque business” designed to “mold you into someone easy to manipulate.”