Last year, there was a horrific Sports Illustrated article about the linebackers on the 1989 USC team: https://www.si.com/college/2020/10/07/usc-and-its-dying-line...

Of the 12 linebackers on the depth chart of that team that year, 5 were dead by 2020, all before the age of 50, with diagnosed or suspected CTE (and only one of them had gone on to play in the NFL).