A few thoughts about Mattison.  First, 4.1 YPC is not bad at all.  There is a pretty long list of RB's whose career average is less than that, some of which are in the HOF.  I'd be more concerned with the trajectory of that YPC number, which has basically decreased annually since he entered the league. That said, I've always felt that Mattison was a stronger complimentary back than he was a #1 option.  Whether it be Chandler or someone else, I sincerely hope they mix somebody else in significantly.  In other words, if Mattison gets 70-80% of the team's RB touches (which I think is highly unlikely) , I think he'll be less effective than if they keep him fresh.  I don't have numbers to prove that.  It's just based on having watched every Vikings game for the past 30 years, including every touch he's had with the team.  He's better when used as a 1-2 punch (doesn't matter if he's 1 or 2), rather than trying to run him into the ground.  That won't go well.