But the most important player making his 2013 debut could be fullback Jerome Felton.
Felton, who sat out the first three games of the season due to a suspension regarding the league's banned substances policy, is preparing for his first game of the season after watching from a distance Adrian Peterson suffer without holes to run through on the first three Sundays of the season.
Things haven't been easy for Felton since his arrival in Minnesota. Last year, shortly after signing a free agent contract, Felton was arrested for drunk driving that cast a cloud as to whether the Vikings would keep him. His other big problem was that, with exception of fullback/mentor Tony Richardson his rookie season, Adrian Peterson didn't like fullbacks. In his view, all they did was get in the way of him doing his thing.
That changed when Felton arrived. He became Peterson's personal bodyguard, snow plow and hired goon. It was his job to keep Peterson from getting a full-on shot from the first defender in his vicinity. He did that job extremely well.
Aside from Peterson's season-opening 78-yard touchdown run, he has struggled to break long runs. Some of the blame has been directed at Peterson not running as hard as he did a year ago when he had "something to prove." Some has been directed at the offensive line, which has struggled to "get a seal here and then you have an alley" for A.D. to run through.
But perhaps the problem has been the absence of Felton. In the one year he has been with Felton, Peterson ran for 2,000 yards – an honor Peterson shared with Felton and one that Felton took pride in.
The Vikings still tried to run offense as normal in their first three games this season, but they didn't have Jim Kleinsasser bringing the sledgehammer and didn't have Felton bearing down on the first line of defense. They had fullback-in-name-only Zach Line. Anyone who saw SMU play knows that, in that offense, a fullback wasn't a prototype fullback, he was a running back. It was convenient that Line suffered a phantom season-ending injury that placed him on injured reserve just in time for Felton to return.
Cassel may be the story Sunday. Bell might make some headlines. But if Peterson is the storyline of the day, it might well be the unheralded secret service agent taking the first defensive bullets for him that makes the biggest difference in the Vikings offense Sunday.
John Holler has been writing about the Vikings for more than a decade for Viking Update. Follow Viking Update on Twitter and discuss this topic on our message boards. To become a subscriber to the Viking Update web site or magazine, click here.