That's why it's a good idea to let them heal and not contribute to declining careers, such as how they mishandled Miles Austin, Marion Barber, Terence Newman, Demarcus Ware.
How did they mishandle these players who had lower body injuries? If you are talking about muscle pulls and that kind of thing, that happens to players all the time in the NFL, so lets not ridiculously act as if that is a Cowboy problem. And, of course, surely you realize the doctors and trainers have to clear players to play, right?
Even so, Newman, for example, played until he was 39 years old, so how exactly did the Cowboys contribute to a declining career? He played 15 years in the NFL and only missed 19 games. He was able to play 6 more years after leaving Dallas.
As for Ware, other than a hamstring issue one season, I don't recall him having "lower body injuries", and he didn't have continuing hamstring problems in subsequent seasons that I'm aware of. It seems it was mainly his back that he had problems with, but even so, he only missed 3 games in 9 years in Dallas, and played a very respectable 12 years. So, what did the Cowboys do to him?
As for Barber, his running style was the main thing that lead to his shortened career.
As for Austin, he did have a history of hamstring problems, but when he had the problem in 2011 the Cowboys shut him down for the last 6 games of the season. and In 2013 when he had a problem, they sat him out for 8 straight games. So explain how he was not given time to heal? Sometimes players just have injury problems.