Justin Houston became the NFL's second highest paid defensive player Wednesday by agreeing to a six-year, $101-million contract, with $52.5 million guaranteed.

After a 22-sack season, Houston believes he's the best pass-rusher in football and the Kansas City Chiefs' deal with him reflects that. Houston has taken the 3-4 outside linebacker market from Clay Matthews' $13.2 million per year to over $16 million annually.

And when asked at a recent charity event whether he and Tamba Hali formed the league's best pass-rushing duo, Houston wasn't shy: "I'd say so. I think everybody should think the same. I think you should think that as an NFL player, think you're the best and believe you're the best. I really do think we are."

But there's a reason the NFL is also known as the "Not For Long" league. If one pass-rusher receives a huge contract, it often leads to the eventual departure of the other. That might soon be the case in Kansas City. Hali, who turns 32 in November, restructured his contract this offseason, taking his $11.5 million average down to $6 million and making himself a free agent next year.

With the Chiefs investing a first-round pick on outside linebacker Dee Ford last year, Hali could be in his final season with the Chiefs.

One important note before we delve into the list: The increasing impact of defensive tackles in the pass-rush could be forming new challengers in the coming years. Ndamukong Suh's move to Miami pairs him with Cameron Wake. Aaron Donald's nine-sack rookie season may reconfigure opinions of the Robert Quinn-Chris Long alliance in St. Louis. Marcell Dareus's 10-sack season helped the Buffalo Bills lead the league with 54 sacks.

But let's forget about what could be for a second, and look at my current top-five pass-rushing duos.

1. Houston-Hali

As Houston has grown, so has the Chiefs' defensive. In their four seasons together, Houston's sack numbers have increased each season -- 5.5 as a rookie, 10 in Year 2, 11 in 2013 and 22 last year. And it's no surprise that the more Houston reached the quarterback, the fewer points KC allowed. Opponents' points per game dropped from 26.6 in 2012 to 19.1 in 2013 to 17.6 last year. The Chiefs learned his value when he missed the final five games of the 2013 season, allowing 25.2 points and 405 yards per game without him.

Over the past four seasons, Houston and Hali have combined for 86.5 sacks. It may very well happen, but it would be a shame to see them break up after the season.

2. Von Miller-DeMarcus Ware, Denver Broncos

Schematically, the Broncos' switch to the 3-4 defense should enable them to outperform the Ravens' Terrell Suggs and Elvis Dumervil this season. Miller enters every season as a candidate for Defensive Player of the Year. He has 49 sacks in 56 career games. The switch to the 3-4 should benefit Ware the most. He averaged 13.9 sacks per season playing in Dallas' 3-4 scheme, but when the Cowboys changed to a 4-3 in 2013 and he played defensive end, Ware only mustered six sacks. And last year, he had 10 playing as a 4-3 DE in John Fox's defense.

Broncos defensive coordinator Wade Phillips should make it easy for Ware and Miller to put up bigger numbers this year.

With 26.5 sacks in his past two seasons, Elvis Dumervil has been a deadly weapon for the Ravens. Geoff Burke/USA TODAY Sports

3. Terrell Suggs-Elvis Dumervil, Baltimore Ravens

This is the NFL's senior elite pass-rushing duo. Suggs turns 33 in October, and Dumervil is 31. But you wouldn't know it by their play of late. Suggs had 12 sacks, 32 hurries and 11 pressures last season, while Dumervil put up 17 sacks, 28 pressures and nine QB hits. If you are wondering about how long this duo can last, the top six sackers in NFL history had at least 15-year careers. Suggs is in Year 13; Dumervil in Year 9. As Tiger Woods said this week at the British Open, he doesn't have an AARP card yet and neither do Suggs and Dumervil. In fact, both players have carved out potentially longer careers by making themselves affordable for years to come. Dumervil has a $4 million base salary in each of the next two seasons and $5 million in 2017. Suggs is making $16.5 million total over the next four years.

4. Mario Williams-Jerry Hughes, Buffalo Bills

In 2012, Bills' management recruited Williams in free agency and didn't let him leave the building until he signed a six-year, $96-million contract. He's lived up to his end of the bargain with 38 sacks in three seasons. Hughes ended up being a steal for Buffalo. A former disappointing first-round pick for the Indianapolis Colts, Hughes was traded to Buffalo for linebacker Kelvin Sheppard in April 2013. After three years, seven starts and five sacks in Indianapolis, Hughes emerged as a star with the Chicago Bills. He's had 10 sacks in each of his first two seasons in Buffalo and was rewarded with a five-year, $45-million contract this off-season. It's no wonder the Bills led the league in sacks.

5. Robert Quinn-Chris Long, St. Louis Rams

This battering Ram duo edged out a couple of other notable duos: New Orleans' Junior Galette and Cameron Jordan, Philly's Connor Barwin and Brandon Graham, Seattle's Cliff Avril and Michael Bennett, and Green Bay's Julius Peppers and Clay Matthews. Quinn earned a four-year, $57-million contract with 45 sacks during his first four seasons, while Long makes more than $12 million per year. During his three years with Quinn, Long has averaged 11 sacks per season. Ankle surgery limited him to six games last year, but the Quinn-Long partnership should expect decent numbers this year, particularly with Donald causing blocking problems at tackle.