Here's a key matchup to watch in Sunday's Vikings-Panthers game.
Vikings RB Adrian Peterson vs. Carolina's run defense
The Panthers' defense is allowing 4.7 yards per carry (tied for 25th in the league) and 133.4 rushing yards per game (29th in the league). And now the struggling defense gets to deal with Peterson, the league's leading rusher.
The problem with the run defense has been the interior of the defensive line, which has been easily pushed around by opposing offensive line. Poor DT play from two rookies, Terrell McClain and Sione Fua, has allowed for guards and centers to get to the second level against the linebackers, which is what creates the big plays that the Panthers have been susceptible to.
Once Peterson is able to get to the second level himself, his power, change of direction and acceleration out of cuts can create runs of 20 yards or more. Give him a big hole and a head of steam to attack it, and it could turn into touchdowns.
For the Panthers to stop Peterson, they need better play at the point of attack. That means McClain and Fua need to do a better job of holding their ground and keeping blockers off of LBs Dan Conner, James Anderson and Jason Williams. From there, the defense needs to rally to the football and gang-tackle Peterson. Otherwise, he'll break free and pile up yardage.