They don't seem to use Starks as a blocker - although maybe he has to stay home on blitzes. Starks doesn't even run pass patterns, he just drifts downfield on pass plays as the check down. Kind of sad how predictable his role is.
There always seems to be a glut of decent running backs; it's the easiest position on the team to fill. Yet all we got is a battered starter and a worthless #2.