Thomas Davis as Instrumental to Carolina Panthers' Success as Luke Kuechly

If Luke Kuechly is the heart of the Carolina Panthers defense, Thomas Davis is its soul. 

Davis remains overshadowed by one of the game's top defenders despite being one of the NFL's top linebackers in his own right. 

Instead of comparing the two, their body of work should be looked at as a symbiotic relationship that forms the league's best linebacker tandem.

"It’s just little things that, maybe it’s not drawn up that way, but it works," Kuechly told the Charlotte Observer's Joseph Person in November. "That’s kind of what’s fun about him is he sees the same things. I think we play well with each other, and it’s fun."

Kuechly's comment came two weeks before the Panthers hit their stride as a team, but his words proved to be prophetic because Davis took his game to another level that following weekend. 

According to Pro Football Focus (subscription required), Davis received his best grade of the season Nov. 16 against the Atlanta Falcons. His performance Saturday against the Arizona Cardinals in the first round of the playoffs was among his best efforts of the season, too. 

The Panthers defense absolutely dominated a Ryan Lindley-led Cardinals squad. In fact, the Cardinals' 78 total yards were the lowest offensive output in NFL playoff history. 

Davis' complementary play was evident throughout the contest. 

The 10th-year pro flew about the field as if he were a rookie hungry to make an impact in his first playoff game. Davis certainly isn't a rookie, and it's amazing he is still one of the game's most athletic linebackers after suffering three ACL injuries to the same knee during his career. 

His play at his age (31) considering his injury history still amazes those who have been around the game for years, as evidenced by the Twitter reaction of ESPN's Matt Williamson during Saturday's contest: 

Davis' stat sheet wasn't completely stuffed. He only registered seven tackles, but two of those tackles were for a loss. His overall play, though, was as good as or better than that of anyone else who took the field for the Panthers, according to Pro Football Focus' Thomas Maney:

"

Most of his work came unblocked and he didn’t necessarily come up with the highlight-reel plays that his teammate did. This was still a great performance from Davis who collected seven tackles and five stops. He was particularly good limiting yards after the catch in the passing game, consistently closing and finishing on passes into the flat. Davis allowed the Cardinals to gain less than 20 yards on seven passes into his coverage.

"

Davis is the complete package at linebacker. He's stout against the run, athletic in coverage and a sound tackler, displays strong recognition skills, possesses impressive closing speed and provides scheme versatility. His entire repertoire was on display Saturday. 

At the onset of the game, Davis' versatility was readily apparent. 

When the Cardinals lined up for their first offensive snap, the veteran linebacker didn't line up at his traditional position of weak-side linebacker. Davis was directly over the Cardinals' starting tight end, Daniel Fells, as the starting strong-side linebacker (see: below).

Credit: NFL Game Rewind

During the play, Davis would normally play the run first or drop into coverage. Instead, Panthers defensive coordinator Sean McDermott called a strong-side dog (a blitzing linebacker). The Georgia product was blocked effectively by Arizona's running back, but it's merely an example of how Carolina's coaching staff can get creative with the veteran. 

Davis' ability to play all three linebacker positions became doubly important this season due to multiple injuries on the strong side. Veteran Chase Blackburn only started two games due to a knee injury before being placed on injured reserve. Backup A.J. Klein was bothered by an injured ankle in recent weeks, which allowed an undrafted rookie out of Florida Atlantic, Adarius Glanton, to start the Panthers' three biggest games of the season.

While Glanton is an athletic upgrade over Blackburn and Klein, he is ideally suited to playing weak-side linebacker. Thus, Davis switched multiple times to the strong side when the Panthers defense presented its 4-3 base set. 

The defense spent most of Saturday afternoon in nickel defense, though. 

The Panthers didn't need the extra linebacker with Davis and Kuechly plus safeties Tre Boston or Roman Harper playing close to the line of scrimmage. 

Davis showed the ability to hold blocks at the point of attack to help stagnate the Cardinals' rushing attack. The linebacker didn't need to register a tackle to make a play. 

In the screenshot below, Davis read the run and effectively filled the hole while taking on a block from Cardinals right guard Paul Fanaika. 

Credit: NFL Game Rewind

Due to Davis' ability to take on the blocker, Cardinals running back Kerwynn Williams was forced to bounce his run to the outside of the Cardinals' left tackle. Kuechly scraped over the top to stop the running back, but Davis set everything up by effectively maintaining his gap responsibilities. 

The veteran also registered two tackles for loss. The screenshot below was taken during Davis' second such effort. 

Credit: NFL Game Rewind

There are two impressive aspects of Davis' play pictured above.

First, his play recognition is exceptional. Kuechly is known as having the best instincts of any linebacker in the NFL. However, Davis already took his initial step toward the line of scrimmage to tackle the running back, while Kuechly was still making his read. Davis saw the offensive tackle to his side blocking down and immediately went to fill the running lane.

Once Davis made the correct read, he registered a solo tackle against Williams.

The linebacker's ability to stop the run is only part of his game. Davis is arguably better at dropping into coverage. After all, the former Georgia Bulldog played quite a bit of safety during his time in Athens. It's still evident 10 years later that the linebacker is comfortable working in space. 

On 3rd-and-8 from the Cardinals' 22-yard line early in the first quarter, both of Carolina's linebackers took deep drops. Lindley correctly checked down to the open running back in an attempt to gain a first down and establish some type of rhythm.

Davis shut it down. 

Credit: NFL Game Rewind

At the time of the screenshot, the ball is coming out of Lindley's hand when Davis recognizes the play. The linebacker is already driving off his back foot to close on the football. At this point, Davis is 20 yards away from running back Robert Hughes. 

Keep in mind that Hughes, 25, is 235 pounds and not easy to tackle one-on-one, while Davis is six years older and listed at the same weight.

The linebacker closed on the ball like a crazed dog and made the open-field tackle two yards short of the first down. It was an impressive feat of athleticism that Davis routinely makes. 

Due to the Panthers' heavy reliance on their nickel defense against multiple-receiver sets and instability at strong-side linebacker, Davis' versatility is absolutely crucial to the team's overall success. He may not have been named to an All-Pro team or even a Pro Bowl during his career, but awards aren't everything. Davis' skill set is as good as that of any other 4-3 outside linebacker in pro football. 

Kuechly can't do it all. What the NFL's reigning Defensive Player of the Year doesn't track down, Davis will.

"That’s why I think they make such a good combination, is that T.D. understands, he gets it, and he follows Luke’s lead,” Panthers head coach Ron Rivera told Person. "And I think that frees T.D. up to really run and do the things he does really well."

Brent Sobleski covers the NFC South for Bleacher Report. Follow him on Twitter.