In the previous post, I suggested Brett Favre would open things up for Adrian Peterson to have a career year, and Jason wondered how much more we can really expect from AP. I can certainly be more specific: I believe a passing threat would help Peterson to be a more consistent runner.
Adrian Peterson averaged 4.8 yards per rush in 2008, and this hefty average was buoyed by a lot of long runs. Peterson led the league with 20 runs of 20+ yards. But according to Football Outsiders, Peterson had a success rate of 46%, which ranked 23rd in the league. Peterson had a lot of dazzling runs, but he also got stuffed at the line of scrimmage a lot. This was most evident in the final two games; here are the yards Peterson gained on each of his carries.
versus Giants: 1, -4, 1, 4, 3, 0, 3, 3, 67, -1, -1, 3, 7, 2, 6, 5, -2, 0, 7, 1, -2
versus Eagles: -1, -1, 2, 2, 6, 2, 40, 6, 0, 6, 1, 3, 0, 2, 0, 3, 0, 5, 5, 2
Perhaps the immensely talented Peterson tries to break too many runs to the outside and thus gets stopped quickly (I sensed this in the second half of 2007, but not 2008). Or perhaps Peterson gets stuffed a lot because defenses fear the Viking run but don't fear the Viking pass. The defense is crowding the line, focusing on stopping Peterson, because he's been more likely to beat the opponent than Tarvaris Jackson, Kelly Holcomb, Brooks Bollinger, or Gus Frerotte.
That's why I think a legitimate passing threat would make Adrian Peterson a more successful runner. I don't know that his yards per rush would be higher, and I certainly doubt his total yards would be higher. But Peterson could become a more consistently productive runner. My hope would be that those runs of -1, 0, or 1 yard could more frequently turn into runs of 3, 4, or 5 yards. Those types of runs don't make Peterson look like a stud, but they do help the Vikings pick up first downs and drive down the field.
I do think Brett Favre would provide this passsing threat so that the Viking running game could become more productive by becoming more consistent. By threat, I mean the potential for positive passing plays, enough to force the defense to account for the pass (I still recognize the potential for negative passing plays, too).
But while I don't believe Tarvaris Jackson provides this thread, I do think Sage Rosenfels could. That's why I'd prefer the Vikes start Rosenfels and see what he can do.