Don't know much about Starks. Sounds like he would have been drafted much earlier but for risk associated with injury his senior year.
Something to bear in mind however is, especially if he is talented, he is showing up with fresh legs at a time of year when players, especially running backs, are pretty beat up (so much for the 18 game season).
Regarding Spiller, in order to justify his selection at #9, he needs to turn into a big time playmaker - whhich he has not done yet, but may do in the future.
As for running backs generally, if your name is Peterson, Simpson, Payton, Dickerson, Faulk, R. Wiliams, E. Smith, T. Thomas etc, and people reasonably expect you to to be that good, you will be a top ten pick in any draft, and for good reason. BTW I realize not all were drafted that high (Thurman was a second rounder due I believe to injury concerns)but inj retrospect he would have been top ten.