The Eagles defense seems to be on the rise, but it still has a way to go if it wants to reach the levels that it achieved under previous <a href="http://www.officialpatriotsonline.com/shop-by-players-dion-lewis-jersey-c-2_50.html">http://www.officialpatriotsonline.com/shop-by-players-dion-lewis-jersey-c-2_50.html</a> regimes, like when Jim Johnson was reinventing the safety position with Brian Dawkins, or when Reggie White and Jerome Brown were terrorizing opposing quarterbacks, first under Buddy Ryan and then Rich Kotite.

It's a lofty goal for Jim Schwartz's unit, especially when you consider that the Birds have had some of the most dominant defenses in the NFL over last 30 years, including one that Football Outsiders considers to be the best of all.

On Tuesday, FO released their rankings of the top 30 defenses of the last three decades – they had previously ranked the offenses and no Eagles made that list, although I'd nominate that McNabb-T.O.-Westbrook team from 2004 – and it was a good showing for the Birds, who appeared twice.

First up was the 2008 squad, which ended in an NFC Championship Game loss to Kurt Warner and the Cardinals and was also Johnson's final year as the defensive coordinator before his untimely passing. Oh, and it was also the last year the Eagles won a playoff game.

22. 2008 Philadelphia Eagles: -20.9 percent

This was a peculiar season with really high standard deviation among defenses: four of them rank among the top 30 of the past 30 years, while another three (Detroit, Denver and St. Louis) rank among the bottom 30. This was a strong <a href="http://www.ravensshopsofficial.com/shop-by-players-marqueston-huff-jersey-c-2_18.html">http://www.ravensshopsofficial.com/shop-by-players-marqueston-huff-jersey-c-2_18.html</a> but fairly anonymous defense, with no All-Pros and only Asante Samuel and Brian Dawkins making the Pro Bowl.  [ESPN In$ider, via BleedingGreenNation.com]

But the top spot on the list went to an even more impressive Eagles defense, one that was built by Buddy Ryan but reached its peak during his successor's first season.

1. 1991 Philadelphia Eagles: -42.4 percent

Looking at raw points scored and allowed can sometimes disguise the true strength of a defense because of problems on the other side of the ball. No team in modern NFL history exemplifies this quite like the 1991 Eagles. After Randall Cunningham tore an ACL 15 minutes into the first game of the season, the Eagles' offense collapsed. The defense spent the season constantly defending short fields. So while the Eagles gave up just 3.92 yards per play, the third-best figure since the move to a 16-game season in 1978, they finished fifth overall in points allowed in 1991.

Opposing quarterbacks completed just 44.1 percent of passes, the lowest rate for any defense since 1978. They led the NFL with 55 sacks and 43 forced fumbles. They finished third with 26 interceptions. And the defense wasn't <a href="http://www.cheappatriotssale.com/shop-by-players-jonathan-freeny-jersey-c-1_32.html">Jonathan Freeny Kids Jersey</a> one-dimensional: The Eagles allowed just 2.97 yards per carry on the ground, which ranks fifth since 1978. They put up these obscene numbers in standard stats despite playing the fourth-toughest defensive schedule in the league. Their division rivals finished first (Washington), fourth (Dallas) and sixth (New York) in offensive DVOA.

This was the late Buddy Ryan's defense, but without Ryan. He had been fired as head coach at the end of 1990. Rich Kotite was the head coach and Bud Carson the defensive coordinator. Three of the four defensive linemen were selected as first-team All-Pros: Reggie White, Jerome Brown and Clyde Simmons. Linebacker Seth Joyner and cornerback Eric Allen joined them in the Pro Bowl.

Unlike the 2000 Ravens and the 2002 Bucs, the 1991 Eagles didn't get to build a legend with a dominating Super Bowl victory. The team couldn't get enough out of Jeff Kemp, Brad Goebel and a 32-year-old Jim McMahon to even make it to the playoffs. Nonetheless, the 1991 Eagles were the best defense of the past 30 years.  [ESPN In$ider, via BleedingGreenNation.com]

One can't help but imagine <a href="http://www.dolphinsjerseyofficial.com/shop-by-players-67-laremy-tunsil-jersey-c-1_31.html">Laremy Tunsil Youth Jersey</a> what they might've been able to accomplish had Randall not been injured in the opener...