Erik Williams is an excellent example. He was so great before that car wreck. Here are some others that come to mind.
The Cowboys’ first “star” QB, Don Meredith, had to retire early in part because of multiple injuries including a broken nose twice, multiple concussions, broken ribs and a knee injury. Meredith was only 31 when he retired. He comes to mind first.
The great Harvey Martin, a co-MVP with Randy White in SB XII, had his excellent career shortened by injuries as well as off-field issues.
The two biggest wastes of their talent had to be the great Duane Thomas and “Hollywood” Henderson.
Thomas had a ton of talent but He was also a “head case”. He was so good, he was compared to the great Jim Brown. But his bad attitude led to him being traded after only 2 full seasons with Dallas. He was out of the league after only 4 years in the NFL.
Henderson was an absolute stud of an athlete at LB. Big, fast and versitile, Tom Landry said he was the most gifted athlete he had coached. But a cocaine habit led to him being released after 4 seasons. Like Thomas, he was an absolute beast but blew with off the field problems.
Tony Romo and the injuries that weighed him down at the end of his career have to be on this list. He was at the height of his mental command of the game, but sadly his body failed him in the end.