I'll bring this back up again RE: Murray, and it's the same argument that's used against Mathews: the "injury prone" label.
While our minds see a guy injured two years in a row, plus injuries in college, we think, "Injury Prone." Human brains are designed to identify patterns and assign them to groups of data - it helps us process things.
With RBs, however, it may not be fair.
This article is one of the best I've ever seen related to this potential fallacy. I say potential because I can see both sides, but this article is hard to argue with.
Regarding Murray, I lean toward what Coop is saying RE the injuries - there's not a pattern of consistently injuring the same joint, leg, etc. in the same leg. These weren't chronic injuries - they're random. They happen.
And when they happen to a Murray or Mathews, and those guys get tagged as injury prone, talents can be purchased for far less than their actual value.