This weekend, the Seattle Seahawks will make the journey from the northwest to the northeast to visit Lincoln Financial Field. With them, the defending Super Bowl champions will bring their hallmark defense, a unit that gave credence to the old adage that defense wins championships.

The Seahawks' vaunted defense hasn't lost a step from last year's impressive campaign. Following Sunday's games, the Seahawks rank first in the league in total yards allowed per game. They are only team in the league to allow fewer than 300 yards per game.

Chip Kelly's offense ranks fourth in the league with over 410 yards per game, which means this weekend's clash will pit one unstoppable force against a seemingly impenetrable wall.

Kelly trusts his offense. But he said Monday that he also understands how good the Seahawks' defense is. The unit has limited its last two opponents to just three points apiece.

"They've got players at every single position on the defensive side of the ball," Kelly explained Monday. "There's a reason they won the Super Bowl last year, and there's a reason they've held the last two teams they've played to three points.

"They've got a lot of really talented players over there."

Kelly's right; for a team studded with marquee names, the majority of Seattle's stars play defense. The focal point of the unit is its excellent secondary, headed by cornerback Richard Sherman and safety Earl Thomas, both Pro Bowl players.

The two have combined for four interceptions this season and have played a big role in limiting their last three opponents to 116 passing yards per game.

"It'll be the best secondary that we play," Kelly said frankly Monday.

Kelly then called Sherman "probably the top corner in the league", citing Sherman's penchant for interceptions  -- 23 since 2011, eight more than any other play in the league during that time.

"[Sherman]'s a smart player," Kelly continued, "an intelligent player. He's big, he's physical, he's got great ball skills."

Of course, two world class players can only do so much for a defensive unit of 11 men. The rest of the Seahawks' defense is to be respected as well, including their two excellent pass rushers, defensive ends Cliff Avril and Michael Bennett. The two have combined for 10 of the Seahawks' 18 sacks this season.

"They've got a bunch of guys that are fast and athletic," Kelly said. "Cliff Avril can really cause some problems, Michael Bennett can cause some problems, and their linebackers can run."

Seattle's defense, Kelly said, is a very balanced attack with talent at each position. They keep their eyes on the quarterback, disrupt routes, and get after the ball well. With three extra days to prepare, Kelly said he and his coaches have been taking note of every matchup between his offense and the Seahawks' defense. Against such a talented unit, every edge will be helpful.

"We always concern ourselves with the personnel on the opposite side," Kelly explained. "You've got to know what they're in, how things are working, and what match-ups you're going to try to exploit or try to attack."

And if there's any head coach in the league with the chops to exploit Seattle's defense, it's Kelly.