Things change fast in pro football and no position sees that as much as running back. One week a guy is the king of the mountain, the next he's got a calf injury that turns into bilateral Achilles tendonitis and then later suffers a PCL injury and he's sidelined for the whole year after he was taken first overall.

The NFL has held one preseason game already and will soon see the entire league enter the exhibition portion of their schedule.

Welcome to my 12-part mock draft series, where I'll be drafting from every position — 1 through 12 — in a standard 12-team Yahoo fantasy football league to uncover the optimal strategies and roster constructions at each spot.