There isn't a more impressive tandem of second-level defenders in the NFL than Luke Kuechly and Thomas Davis in Carolina. These two wreak havoc on opponents with their collective speed, quickness and freakish athleticism, but their instincts and football aptitude are what truly separate them from their counterparts. Kuechly and Davis appear to know the opponent's plan before the snap; their keen anticipation and awareness allow them to blow up plays between the numbers. With the Panthers leaning heavily on their stingy defense to carry the team into the postseason, this dynamic duo deserves consideration as one of the most feared units in football.

The "old heads" on the edges continue to terrorize opposing quarterbacks throughout the league. Terrell Suggs and Elvis Dumervil are on the back nine of their respective careers, but each player knows how to get home off the edge, as evidenced by their 29 combined sacks in 2014. Suggs remains one of the most explosive power rushers in the NFL, flashing an array of rugged moves that overpower blockers in one-on-one situations. Dumervil is a dynamic pass rusher with exceptional first-step quickness and burst. He complements his speed rush with a sneaky dip-and-rip maneuver that enables him to slip under blockers off the corner. The Ravens' aggressive scheme creates plenty of one-on-one opportunities for Suggs and Dumervil, and the team's pass rush still ranks as one of the best in the league, despite featuring one player who is 32 (Suggs) and another who is 31 (Dumervil).

Todd Bowles inherited one of the top defensive lines in football when he took over Gang Green. The Jets' imposing front features two of the most disruptive interior defenders in the NFL in Muhammad Wilkerson and Sheldon Richardson (pictured). The duo absolutely annihilates opponents at the point of attack, exhibiting exceptional strength, power and agility while blowing past blockers on the way to the quarterback. Quinton Coples has been a bit of an underachiever based on expectations, but he has posted 16.5 sacks in three seasons while playing out of position (3-4 OLB), which suggests he could blossom into a legitimate threat in Bowles' aggressive defense. Throw in first-rounder Leonard Williams' potential as a versatile playmaker, and it's clear: The Jets' talent and depth along the D-line will lead to a lot of sleepless nights for offensive coordinators around the NFL.

When the Broncos paired DeMarcus Ware with Von Miller, the defense surged up the charts behind a new version of the "Orange Crush." Ware not only provides veteran leadership, but he also flashes the vintage skills that have helped him rack up 127 sacks in 10 seasons. The savvy vet routinely dips into his bag of tricks to pull out a slick maneuver that allows him to get home. (See: This fake spin move against 49ers LT Joe Staley.) Miller simply blows past blockers with an explosive first-step that makes him nearly impossible to contain. He routinely wins on a conventional speed rush or a bend-and-burst move that showcases his exceptional athleticism, agility and snap-count anticipation. Given new coordinator Wade Phillips' reputation for crafting some of the top defenses in NFL history, the Broncos' pass rush could destroy opponents with Ware and Miller crashing off the edges.

When Chip Kelly traded LeSean McCoy to the Buffalo Bills early this offseason, few expected the Eagles' running back rotation to eventually improve. Yet, the Eagles suddenly sport a frightening backfield trio of DeMarco Murray, Ryan Mathews and Darren Sproles (pictured). Murray is the reigning NFL rushing king and sports a downhill running style that is better suited to Kelly's zone-based system than McCoy's shifty approach. Mathews is a versatile playmaker capable of ripping off 100-yard games as a runner or receiver. The sixth-year pro has battled through a host of injuries throughout his career, but a pair of 1,000-yard seasons illustrate his raw talent. Sproles is the most explosive returner in the game, but it is his electric talent as a rusher/receiver that scares defensive coordinators around the NFL. In Kelly's warp-speed offense, the thought of defending a diverse, three-man backfield will induce headaches in defensive meetings.

The "Legion of Boom" is unquestionably the backbone of the Seahawks' suffocating defense. The secondary sets the tone with airtight coverage and "bang-bang" hits, particularly between the hashes. Thus, the Kam Chancellor-Earl Thomas safety tandem deserves mention as one of the most feared groups in the NFL. Thomas is the ultimate center-field safety with his extraordinary instincts, awareness and range. He protects his aggressive cornerbacks with his ability to float over the top, yet it is his superb communication that keeps the "LOB" in line. Chancellor is the menacing force every team covets in the middle of the field. Measuring 6-foot-3 and 232 pounds, he's a "thumper" capable of snuffing out runners in the hole or receivers venturing over the middle of the field. The big-bodied box safety is the perfect complement to Thomas.

In a pass-happy league, it is imperative for an elite D to have at least three cornerbacks capable of winning one-on-one matchups. The Jets clearly have the best threesome, with Darrelle Revis, Antonio Cromartie and Buster Skrine joining forces. Revis is back to putting receivers on the island. He is a technical marvel with an extraordinary football IQ. Playing behind a ferocious pass rush this season, Revis can be even more aggressive in coverage, with the ball coming out quicker from the pocket. Cromartie is capable of strangling receivers with his aggressive bump-and-run tactics. His combination of length and ball skills dramatically shrinks the QB's strike zone. Skrine doesn't have the reputation of his Pro Bowl partners, but he's a quality third corner capable of locking down WR3s. Given Bowles' willingness to attack opponents with a barrage of Cover 0 pressures (all-out blitzes without safety help), these CBs will have plenty of chances to showcase their impeccable cover skills.

It shouldn't come as a surprise to see the Rams' defensive line on this list, based on how heavily the front office has invested in the unit. The Rams' D-line rotation features five first-round selections: Robert Quinn, Aaron Donald, Michael Brockers, Chris Long and Nick Fairley (who was taken in Round 1 by Detroit in 2011 but signed with St. Louis this offseason). The Rams should be able to overwhelm opponents with their collection of talent in the trenches. From controlling the run with Brockers and Fairley to harassing quarterbacks with Long, Quinn and Donald, the Rams have the ability to attack the line of scrimmage with a number of big-bodied athletes with exceptional size, strength, power and explosiveness. With coordinator Gregg Williams adept at using blitzes to create one-on-one opportunities for his disruptive defenders at the point of attack, the Rams should pummel opponents at the line of scrimmage on their way to becoming one of the NFL's premier defenses.

If Jim Schwartz was able to help the Bills' defensive line terrorize opponents without heavy blitzing, imagine how much chaos this D will create with blitz master Rex Ryan at the controls. Ryan's high-pressure tactics will produce more one-on-one chances for Mario Williams and Jerry Hughes on the edges, with linebackers and defensive backs joining the pass rush as fifth and sixth defenders at the point of attack. Kyle Williams and Marcell Dareus are imposing defenders on the interior with the capacity to blow up runs or disrupt passing games with frenetic playing styles. Dareus, in particular, is a dominating force -- with 28.5 sacks in four seasons, including 10 in 2014. Considering the success the Bills' front line enjoyed under Ryan protégé Mike Pettine in 2013 (the unit accounted for 41 of the Bills' AFC-high 57 sacks), the return to a hybrid scheme should keep the group playing at a high level this season.

When the Joneses decided to invest top draft picks on the O-line, they reversed the fortunes of the franchise -- giving Jason Garrett the option of relying on a physical, run-first approach to knock off heavyweights around the NFL. With three first-round picks (Tyron Smith, Travis Frederick and Zack Martin) and a pair of blue-collar blockers (Ronald Leary and Doug Free), Dallas' starting quintet pummeled defenders at the point of attack in 2014, allowing DeMarco Murray to lead the NFL in rushing. The unit could be even better in 2015 with talented rookie La'el Collins possibly joining the starting lineup at left guard. The undrafted free-agent signee was considered a first-round talent before a police investigation on the eve of the draft torpedoed his stock. (Collins spoke to police about the shooting death of his ex-girlfriend, but he was never labeled a suspect.) Thus, the NFL's top O-line added another blue-chipper to a group that's set to dominate the game for the next decade.