The Green Bay Packers are one of seven undefeated teams in the NFL. The offense receives a lot of attention because of the quarterback, but it's the defense that has been most impressive when breaking down this team on film.

Mike Pettine is in his second year at defensive coordinator. Since he arrived in Green Bay, the team spent a ton of assets retooling that unit, drafting three first- or second-round choices in the secondary (Jaire Alexander, Josh Jackson, and Darnell Savage), spending a first-round pick on one pass rusher (Rashan Gary), and giving out big free agent contracts to two others (Za'Darius Smith and Preston Smith).

This team lives in its subpackage, whether it's in their multiple varieties of nickel (five defensive backs) or varieties of dime (six DBs). There's a lot of speed on the field at all times. The Packers also have a multitude of looks with their pieces in the front seven, mixing and matching players like Kenny Clark, Preston Smith, and Za'Darius Smith all around the front, attacking offenses from different angles.

This unit also just PLAYS angry. They have a very well-defined play personality on film, flying around the field and playing an attitude and palatable toughness. They have gotten after the three offenses they've played so far (Chicago, Minnesota, and Denver), and have won the "toughness" battle in each of those contests.

Schematically, their usage of pressure looks has been very impressive. Pettine's group lines up in a bunch of different looks and gives you a lot to prepare for. One blitz that they specialize in though? It should look familiar if you're a longtime reader of this column. It's the Double-A Gap or Mug front.

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You have to have your protection rules buttoned up when you take on this team. I don't believe that Chicago had everything straightened out back in Week 1, and Green Bay took full advantage, with several big hits on the quarterback Mitchell Trubisky due to busted protections.

I'm going to get a bit into the weeds here, so feel free to skip this if you want to continue with the Packers breakdown. Green Bay did one little tweak in this front that I think resulted in these broken plays. You'll notice that one of the 3-technique defensive tackles in some of those plays is actually extra wide, almost out over the offensive tackle. For this reason, I think Chicago may have gone away from a typical three-man slide protection and gone to a four-man slide protection. Regardless, it wasn't always communicated all the way across the formation, and busts happened, but part of the credit has to be given to Green Bay for this slight wrinkle in the front, throwing Chicago for a bit of a loop pre-snap. Alright, back to the Packers breakdown.

The Packers don't just rely on busted protections though. They've also done a really good job of breaking down protections themselves to create free rushers on the quarterback. This is something that Eagles Hall of Fame coach Jim Johnson was so good at doing, both with fronts like the one above and others. One thing they've excelled at is creating opportunities for explosive athletes such as the rookie Savage to get home scot-free.

The Packers essentially cut the protection in half by occupying the center with a defensive lineman on his outside shoulder. The guard and tackle are now isolated without the center providing help. With two linemen for them to worry about, the Packers can now send a third rusher, typically from depth so that he's not accounted for, who is able to get free to the passer. These are extremely well executed, and a great way to attack slide protection schemes.

Green Bay isn't just going to just send the house on every play though. In fact, the Packers have only blitzed 29 times so far this season, which is pretty much right in the middle of the, yes, pack when compared to the rest of the NFL. The threat of pressure is always present, however, so protection schemes have to account for that fact. Knowing that, Green Bay has actually gotten pressure using an aggressive three-man rush.

These three-man rushes result in eight defenders back in coverage. This shrinks passing windows, confusing things for the quarterback. Also, by showing pressure pre-snap, the defense alerts the quarterback that he may want to hit his "hot" read and get the ball out quickly. By then falling out into eight-man coverage, you now can trick the quarterback and run defenders through the throwing lane, potentially creating a turnover.

The Packers rank second in the league right now with an opposing quarterback rating of 63.1, allowing just a 56.6 percent completion rate (third in the league). They've racked up 12 sacks (which leads the NFC), and lead the league with eight takeaways (four interceptions and four fumbles). They also rank second in the league in touchdown efficiency, allowing a touchdown on just four of 38 drives (10.5 percent).

Schematically, the Packers are going to give the Eagles a lot to think about on Thursday night. Carson Wentz and the offense have to be ready, on a short week, to step up to the challenge from a mental standpoint.

From a personnel standpoint, the Packers are also a very challenging front, and it starts with their two free agent additions, Za'Darius Smith and Preston Smith.

These two are interchangeable pieces. They both line up outside. They both line up inside. Za'Darius Smith has more power and can win with pure mass, barreling blockers backward into the quarterback. Preston Smith wins with length and athleticism, using those long levers to get the ball on the ground. Both are also excellent on stunts up front, so pairing the two together on the same side is very dangerous for opposing offenses. These two will get matched up on pretty much anyone on the Eagles' offensive line.

Defensive tackle Kenny Clark has a little bit less versatility than the Smiths, but he will still line up just about everywhere on the inside. Nose tackle, 3-technique, 5-technique, standing up over the center, it doesn't matter. He brings the same play personality to the field every time. Clark is stout, very good with his hands, plays with a strong motor, and can collapse the pocket as well. He'll see most of his reps against Isaac Seumalo, Brandon Brooks, and Jason Kelce.

I mentioned that the Packers also live in their subpackages, so they play with a ton of defensive backs on the field. The DB who has impressed me the most is cornerback Jaire Alexander. This kid is explosive, competitive as all get-out, and very instinctive. He runs routes better than receivers, is almost always where he needs to be, and fights with whoever he lines up against on the field. On this week's Eagle Eye in the Sky podcast fueled by Gatorade, I read my notes on Alexander coming out of college. He looks very similar to the player patrolling the Louisville secondary from 2015-17.

Fran Duffy is the producer of the Emmy-nominatedEagles Game Planshow which can be seen every gameday during the season on NBC10 in Philadelphia. He is also the host of two Eagles-related podcasts,Eagle Eye in the Sky, which examines the team from an X's and O's angle each and every week as well as theJourney to the Draft podcast, which covers college football and the NFL Draft all year round. Fran also authors the Eagle Eye in the Sky column, which runs four times a week during the football season to serve as a recap for the previous game and to preview the upcoming matchup. Prior to joining the Eagles in 2011, Duffy was the head video coordinator for the Temple University football team under former head coach Al Golden. In that role, he spent thousands of hours shooting, logging, and assisting with the breakdown of the All-22 film from the team's games, practices, and opponents.