The biggest difference between what the Lions defense and what the Eagles ran is the skill of those two defensive tackles: Nick Fairley and Ndamukong Suh. Both are Pro Bowl-caliber players who are disruptive on the interior, posing a considerable challenge for Kelce and guards Evan Mathis and Todd Herremans.
They also stand out to running back LeSean McCoy, the NFL's second-leading rusher, who must navigate against the NFL's No. 3 rushing defense. The Lions defensive line might look inviting for rushers because of the large gaps, but the numbers prove otherwise.
"It's so open, because the guys are so wide," McCoy said. "The difference with this wide-nine is the two guys inside, Fairley and Suh, they kind of dominate. So it helps it out differently than a lot of wide-nines."
Kelce said that the two defensive tackles are "on a different level" than most interior combinations. Kelce said the most comparable skill set to Suh was that of Arizona's Darnell Dockett, although they're used differently. Suh is more of an an upfield player and already has 51/2 sacks this season.
Kelly has vivid recollections of Fairley. When Auburn beat Oregon for the national championship in January 2011, Fairley dominated Kelly's Ducks. He recorded five tackles, one sack and a forced fumble and earned the game's defensive MVP honors. Now in his third NFL season, Fairley is beginning to live up to his promise.
"He's very, very difficult to block," Kelly said. "He's a lot more athletic. He's physical at the point of attack, but he can get off a block and chase plays down. . . . I think the fact that you can put him next to Suh is really what makes that defense go right now."
The defensive tackles attract the attention, but Kelly was also impressed with the defensive ends.
Washburn's focus is on the pass rush, and he has helped developed young defensive ends. First-round pick Ziggy Ansah leads the team with seven sacks. Fourth-round pick Devin Taylor has 21/2 sacks and two forced fumbles. Veteran Willie Young also has three sacks.
The Lions like to rotate linemen, which the Eagles did often under Washburn. That can be difficult to pull off against the Eagles' no-huddle offense. Lions coach Jim Schwartz said there are ways around this, and it's not the first time they've encountered an up-tempo offense.
Schwartz noted that they can rotate every series, and if they force three-and-outs, there are not many tired players on defense. The Lions have the best third-down defense in the NFL, stopping opponents nearly 70 percent of the time.
As well as Nick Foles has been playing, Schwartz still identified McCoy as the key to the Eagles offense. Teams are still loading the box to try to stop the running game. McCoy said that defenses will soon have to make adjustments because Foles is playing "lights out," and that Kelly is still committed to running the ball even against a good rushing defense.
McCoy rushed 19 times for 79 yards against a stout Cardinals running defense on Sunday. He'll see another strong defense this weekend, and the front will look similar to what McCoy watched in practice for two seasons.
"We believe in what we do; I'm sure they believe in what they do," Schwartz said. "We'll be prepared for their runs; I'm sure they'll be prepared for our fronts."