EDEN PRAIRIE, Minn. -- Shortly after the Philadelphia Eagles named Chip Kelly their new coach, Minnesota Vikings defensive coordinator Alan Williams added Kelly's 'blur' offense concept to the list of schemes he needed to scout. Kelly had run the same offense at Oregon, and Williams knew there would be certain things that couldn't be mapped onto an NFL offense.
But there was one thing the Eagles would have that no college team could replicate.
"The back. I can't overemphasize that. It's the running back," Williams said. "The running back is dynamic. I know coach Kelly had some fantastic players where he was in Oregon, but the back is just fantastic."
LeSean McCoy was one of the more dangerous running backs in the league before this season, but in Kelly's hands, he's become one of its most feared players. McCoy leads the league with 1,744 all-purpose yards, which already represents his best season total and puts him ahead of the Vikings' Cordarrelle Patterson -- who is No. 2 with 1,629 all-purpose yards -- without the help of a single kickoff return. McCoy is the fulcrum of the Eagles' offense and the player the Vikings will spend the most time preparing to stop before Sunday's game at Mall of America Field.
"He's like a human joystick right now," defensive end Jared Allen said. "McCoy is making people miss in the backfield and then stretching to the sideline and turning nothing into 40 yards. So we have our work cut out for us, but we've got to try to stop him before he starts and once you get your shot, take your shot. If you miss, you miss. We're going to have to rally. We're going to have to pursue the ball heavily this week."
McCoy's presence is far from the only thing that should concern the Vikings. Nick Foles has thrown 20 touchdowns to one interception since taking over for Michael Vick, and the Eagles' offense is uniquely positioned to stress a defense that hasn't reacted particularly well on the fly this season.
The Eagles average 32.1 seconds between plays, the shortest time in the league according to ESPN Stats & Information. The Vikings' defense, on the other hand, has only faced 76 plays that came 32 seconds or less after the previous snap. Only eight teams have seen fewer fast-paced snaps, and as we've seen in the five two-minute drills in which the Vikings have given up leads this season, theirs isn't a defense that's particularly good at reacting on the fly.
"It's going to be tough to simulate," Williams said. "What we're doing is trying to simulate the best we can in practice, to have guys off the field, the substitution part, to not necessarily worry about the type of play that we're getting but the idea that they're coming fast on you. ... You don't want to self-destruct. You want to get lined up. You want to make sure everyone's communicating. It's no secret if you have to call out the coverage and the front that you're playing and then again, it's not necessarily the calls, it's making sure that you're executing the calls, and again, it's tackling."
The Vikings have plenty to worry about on defense, with the possibility cornerback Xavier Rhodes could be out Sunday because of a sprained ankle. But the way their defense has played this year, the Eagles would present a tough matchup regardless of health. And if the Vikings have as much trouble tackling McCoy as they did with Reggie Bush early in the season, they could be in for a long day.