PHILADELPHIA (973espn.com) - Whether the Eagles were 5-0 coming into Sunday’s game against the Minnesota Vikings or anything less than that, this was always going to be the biggest barometer for rookie quarterback Carson Wentz.

The Vikings’ defense may be the best in the NFL, an imposing group where talent meets scheme and the results are often fantastic.

It all starts with the architect, Minnesota’s head coach Mike Zimmer, who is among the most respected defensive minds in football, famous for his widely-copied, double A-gap blitz concept which puts incredible pressure on the opposing QB.

In one three-game stretch this season, the Vikings’ stop unit turned the 2014 MVP, Aaron Rodgers, his 2015 successor Cam Newton, and a two-time Super Bowl winner in Eli Manning into mush.

“Everybody runs the Double-A Gap system, but in my mind, this guy (Zimmer) is the master of it,” Eagles offensive coordinator Frank Reich said. “Zimmer is the master of it. It's his baby. He probably didn't invent it, but he's mastered it. They run every kind of combination there known to man.

“They know exactly what you're doing. What takes it to a different level, is they know what you're trying to do. They know what teams have done to try to counter it. So they try to counter that and it's just a cat-and-mouse game that you play.”

On Sunday, if Wentz ends up being the cat in that fight, you can put to rest any doubts over his future in this league.

DEFENSE, DEFENSE, DEFENSE

The Vikings defense ranks second in the NFL,  allowing 287.6 yards per game, has totaled 19 sacks and held opposing passers to a league-low 65.3 passer rating. It’s also tied for the most takeaways with 12 (7 interceptions and 5 fumble recoveries.)

They have difference makers at all three levels, starting with imposing nose tackle Linval Joseph and pass rushers, Everson Griffen and Danielle Hunter up front, perhaps the most physically imposing linebacker in the game in Anthony Barr, as well as emerging shutdown corner Xavier Rhodes and a top-tier safety who excels in all three phases, Harrison Smith.

Zimmer is a lot like Eagles defensive coordinator Jim Schwartz in that he prefers to get home with four rushers but he is also more willing to blitz because he trusts his CBs, as Minnesota goes four or five deep on the edges.

Despite coming off a bye week Minnesota is still the only team in the NFL to have four players with 3-or-more sacks, Griffen (4), Hunter (4), Brian Robison (4) and Joseph (3).

“When you go up against a Coach Zimmer defense, it's always the biggest challenge of the year,” Reich admitted. “They are so well-coached; very disciplined; tough; fast. Good challenge for us this week – great schemes, very well-coached and good personnel. We have our work cut out for us.”

SAMMY SLEEVES

Ex-Eagles quarterback Sam Bradford has been lights out since taking over the Vikings offense in Week 2 and is currently second in the entire NFL with a 109.8 passer rating. He has also yet to turn the football over with 6 TD passes versus 0 interceptions and his accuracy has shown up in a big way for Norv Turner as he is completing an NFL-best 70.4 percent of his passes.

Much has made about the familiarity both sides have with each other, something Zimmer downplayed earlier this week.

“Very little,” Zimmer said when asked if he’s pressed Bradford for information on the Eagles’ personnel and schemes. “I just asked about the receivers some and what they’re like. But, no not really. It’s very minimal stuff.”

TAKING CARE OF BUSINESS

Neither Bradford or backup Shaun Hill in the opener have thrown a pick this season for Minnesota and the Vikings offense as a whole has yet to turn the football over in five games.

Minnesota’s lone TO on the season came when safety Andrew Sendejo recovered a fumble against Green Bay and then fumbled the football right back.

The Vikings’ plus-11 turnover ratio is the NFL’s best.

“You look at the success, their numbers are not going to boggle you offensively with the exception of turnovers,” Schwartz said. “No interceptions and that goes a long way. You look at their stats across the board, they are not rushing for a very big average, I don't know if you would expect losing Adrian Peterson. But the quarterback is completing a lot of passes, a real high completion percentage. You know, they are not afraid to take a check down.

“They haven't made very many mistakes and I think that has led and as well as their defense is playing, that's been a good formula for those guys. I think a lot goes into that. We've got to find ways to take their security blankets away, make them be more aggressive in attacking the defense, and then also it would help, you make them play from behind, all those things will go together and they haven't done that this year. They have done a good job of playing from ahead and takeaways mean a big thing.”

SPECIAL, SPECIAL TEAMS

Normally the Eagles go in with a huge advantage on special teams under Dave Fipp but that’s not the case, at least in the return game and coverage when it comes to the Vikings.

Minnesota is every bit as imposing on ST as Philadelphia, sporting one of the greatest kick returners in league history, Cordarrelle Patterson, and a punt returner in Marcus Sherels, who rivals Darren Sproles.

Sherels, who ranks third in the NFL with a 16.5 average per return, has already returned two punts for a TD this season, extending his franchise record for career PR TDs to five.

The one area where Philadelphia should have an edge, though, is the actual kicking game as Donnie Jones is significantly better than Jeff Locke and Caleb Sturgis has been far more consistent than Blair Walsh.

OFFENSIVE LINE WOES

The Vikings have been a mess up front this season and are without both of their starting tackles as Matt Kalil and Andre Smith are both on injured reserve. They’re stronger inside where Joe Berger is a solid center and Alex Boone, a former Pro Bowl player in San Francisco, has started to pick it up after a slow start.

That said, the offensive front is the biggest weakness in Minnesota and the Eagles front four needs a bounce back effort from its performance against the Redskins if Philadelphia hopes to win the game.

Even with Peterson, who is also on IR, the Vikings weren’t running the football well but the one thing they do is stick with it.

“I think that's a defensive coaches’ mentality,” Schwartz said when talking about Minnesota’s commitment to the running game. “As a head coach, they have just stayed committed to it. It's opened up some tight end stuff in the passing game and it's also probably helped their defense out a little bit. I think that all probably goes into it.

“But after watching us on film last week, I mean, they are going to test us. I mean, I don't care if they are averaging one yard a rush. You watch what we did on film last week, you know, they are in their game plan saying right now we're going to run it 65 times and it's our job to make sure that they don't have success doing that.”

973espn.com prediction: If styles really do make fights, the Eagles have the ingredients to give Minnesota some trouble as the home team but that Vikings defense is a little too talented to expect Philadelphia to go over at this stage of its development. Vikings 21, Eagles 16

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen