Ranking these positional units is a very difficult chore. These defenses are the best of the best, and the difference between a unit with a third overall ranking and one ranked seventh or eighth may be very slight. I had to make some tough decisions, and I am sure many of you out there will let me know the error of my ways.
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Defensive line
Julius Peppers is a tremendous player, but he isn't the only Chicago Bear playing at a high level right now. In fact, the Bears have a very underrated and deep rotation, which the coaching staff handles masterfully, and that puts Chicago at the top of the ratings.
Pittsburgh is at No. 2 with the assumption that Aaron Smith will return during the playoffs. Without Smith, the Steelers would be substantially lower. Brett Keisel has had a terrific season, Casey Hampton is very reliable in the middle and some of the other linemen have improved while Smith has been on the shelf.
If I were to pick the very best defensive lineman playing in the postseason, I would probably choose Baltimore's Haloti Ngata. His fellow Ravens linemen, on the other hand, are not difference-makers. Still, like the Steelers' D-line, this group does the job and fits the scheme well. New York's group doesn't have the star power but plays better than the sum of its parts. It's fair to ask, though, whether the Jets' defensive line was wearing down late in the regular season.
Philadelphia, Green Bay and Atlanta are all very well-equipped along the line and should have an advantage against most offensive lines they face. If I were not choosing Ngata as the best defensive lineman, I would select Trent Cole of the Eagles. B.J. Raji of Green Bay is on the verge of stardom, and the Falcons have a deep, active group.
Indianapolis is interesting because Dwight Freeney and Robert Mathis are still terrors off the edge. But the Colts have not played with a lead as much in 2010, and they need the defensive tackle group to continue to play as well as it has in recent weeks.
Kansas City has improved up front from a season ago but still lags behind the others in this category. The Chiefs really need to address the nose tackle position this offseason. The Seahawks have some good players in Brandon Mebane and Red Bryant when they are healthy and on top of their game. But overall, as it stands today, Seattle is in the No. 12 slot.
Linebackers
Pittsburgh wins first prize by a large margin. The Steelers are loaded at linebacker, as usual. They have James Harrison, LaMarr Woodley, James Farrior and Lawrence Timmons. This is a tremendous foursome.
For the sake of this exercise, I am calling Jarret Johnson and Terrell Suggs linebackers, even though both players wear many hats for Baltimore -- and wear them well. The Ravens, Packers and Bears are very close and difficult to differentiate. Brian Urlacher has made a huge difference in his return. Green Bay has Desmond Bishop and A.J. Hawk, who don't get a ton of recognition but are playing great, much like Johnson in Baltimore.
Kansas City, New York, Atlanta, New England and Seattle make up the middle tier in this category.
The Colts, No. 11, are getting a shot in the arm from Gary Brackett, and the Eagles at No. 10 might have a find in Jamar Chaney.
At the end of the spectrum, I see Jonathan Vilma as an overrated player, and there is very little to get excited about on the outside for New Orleans, which is No. 12. It wouldn't surprise me if the Saints' first-round pick were an outside linebacker.
Defensive backs
Green Bay and New Orleans stand well above the rest when I rank the defensive back groups in the playoffs. Both have playmakers at safety and an exceptional pair of starting cornerbacks. The defensive coordinators put a ton of pressure on their corners, because they know that they can get away with it.
After that, it gets a little murky. The teams ranked third to 10th either have a solid group without a lot of star power or have one phenomenal player like Darrelle Revis, Ed Reed or Troy Polamalu and question marks at other spots.
I am very strong in my conviction, though, that the Eagles and Seahawks are the worst off in this department. Though I am high on Quintin Mikell and wouldn't be at all surprised if Asante Samuel made a big play or two in the postseason, the Eagles have been hammered by injuries and don't match up well against teams like Green Bay that use a lot of personnel groupings with extra wide receivers. As for Seattle, Earl Thomas looks like he has a very bright future, but other than him, I see a group that needs a ton of work and is very undersized at the cornerback position. The Colts have also been hit extremely hard by injuries in their secondary.
Special teams
Of all of these categories, this is obviously the one that is most difficult to rank. I am not going to pretend to be an expert on every long snapper, holder and special-teamer in the NFL. But it is clear that some of these teams have a clear advantage in this vastly underrated phase of the game.
Chicago stands alone, though, at the top. Devin Hester is the first reason for this, but the Bears have more good returners than they know what to do with. Their kicking specialists are proven and reliable -- even in harsh weather. But the most important thing for the opponent is simple: Do not kick it to Hester!
Seattle isn't very high on any of my other position rankings, but I do appreciate how well the Seahawks' special teams have performed. Leon Washington is a great returner, and if New Orleans isn't careful, he could sway Saturday's game in the Seahawks' favor.
The Ravens lack a dynamic return man, but Billy Cundiff has become legendary for his kickoffs. Overall, Baltimore's specialists and coverage teams are top-notch. This is an extremely well-coached group from top to bottom; John Harbaugh stresses this phase of the game -- and gets results. The Patriots are similar to the Ravens in this regard.
Returners DeSean Jackson for the Eagles, Brad Smith for the Jets, Reggie Bush for the Saints and Eric Weems for the Falcons should be very fun to watch over the next few weeks, as should the wealth of young return men that Kansas City employs. Any of these players could be the difference in a win or loss.
It would be a shame to be eliminated from the playoffs because of special-teams play. But just ask the Chargers how important this phase of the game truly is. The Packers, Steelers and Colts are the most likely candidates for that fate.
Scouts Inc. watches games, breaks down film and studies football from all angles for ESPN.com.