After two NFL seasons, those questions remain. Murray has missed nine games, including six last season.
Perhaps that's why the Cowboys used a fifth-round pick on running back Joseph Randle in this year's draft.
Murray said he didn't take it personally and welcomes the competition. However, the Cowboys drafted Randle with the understanding that he'd replace Murray should he get hurt. And with the career span of NFL running backs continuing to shrink, it raises concerns about Murray's long-term future.
"It's part of the game," Murray said of his health between shots at the Cowboys golf tournament Wednesday. "It's one thing that they can talk about. I let my game speak for itself, and that's something that I can control. I rather play five games where I play hard, fast and physical and leave it all out there than 16 games soft.
"I'm going to continue to play hard and do what I have to do. That's the one thing that I can control. It's not that I'm not doing what I'm supposed to be doing, it's ... hey, it is what it is. It happens."
Murray said he's making subtle changes to his offseason workouts to help prolong his NFL career. He suffered a fractured ankle toward the end of the 2011 season and a sprained foot last season.
"I would just say they're freak occurrences," Murray said of his injuries. "Sometimes I might be working too hard at times and sometimes I have to take a step back and do less, but still do a little bit. I tend to work myself too hard, whether I'm with the Cowboys or at night (when) I might do stuff -- riding the bike or running hills, things like that. I have to take a step back and really focus on longevity. I'm not doing anything too different as far as taking a step back."