This reminds me of a little mouse that was just sitting there on the sidewalk one day when I was returning home from university. I was surprised that it didn't run away and suspected that something was wrong with it. Sure enough, one of it's legs was turned the other way around. I took it in my hands and carried it home. It just sat in my palms all the way, barely moving. At home I put it in a shoebox with grass, water and some provender, but the next day it was dead. I assume it also had some internal wounds from whatever happened to it.
Practically the same thing also happened to me with a little bunny once. Little furry animals do that when they are about to die. They just sit there in the open and don't move.