Yes they've ranked RB Brandon Jackson significantly higher than RB Ryan Grant. While Grant is one spot ahead of the Raiders RB Michael Bush, Jackson is just one spot behind RB Adrian Peterson. Instead of somehow using that as proof that Jackson should start ahead of Grant, it's more interesting to combine the two backs.
While Grant is a solid runner (and poor at everything else), Jackson did everything else well (except run). Jackson's blocking doesn't surprise me because he was great as QB Aaron Rodgers's protector last season. This agrees with Football Outsiders who ranked Grant as the No. 10 overall rushing back and Jackson as the No. 4 overall receiving back.
While neither can take the place of the other, they should remain the top 2 backs in 2010 and remain perfect compliments to each other.
Who's No. 3? 6th round pick RB James Starks. From my post-draft analysis:
Now they've added a Ryan Grant clone (Grant is 6'1", 222 lbs. and Starks is 6'2", 218 lbs) with speed. He's strictly Ryan Grant insurance, but that's not a bad thing either.
It's possible he's a dud and finds himself spending his first NFL season on the practice squad, but right now I expect he'll win a roster sport. I'm looking forward to seeing him play in the preseason.