Ok, its not like Shipp or Minor is being projected at this. It may be a stretch, but any RB rushing for over 2000 yards is a stretch. If it were Barry Sanders or Walte Payton saying this, it still wouldn't be a shoe-in.
However, Priest is one of the few running backs that this isn't far-fetched with. He put up ~2100 all purpose yards last year. He broke the single season rushing TD record last year. He's gotten consistently better every year as a starter. He's a year removed from his hip injury. He's the centerpiece of the league's best offense. And, with a tougher schedule this year, KC wont be so tempted to sit him after midway through the 3rd quarter just about every game.