Cook heads to camp with the lead over Latavius Murray in the competition for the No. 1 running back role. How the backfield battle plays out will inform Zimmer's response to Priefer. Cook is the most talented runner the Vikings possess. We expect the second-round pick to lock down the top job, relegating Murray to short-yardage situations and Jerick McKinnon to pass-catching downs. If that prediction comes true, Priefer's dream of getting the rookie to return kicks is likely out the window.