There's no doubt that J.J. Watt is the best defensive player in the NFL right now. But who is the second-best? SI.com's staff makes their cases.

2014 was the year of J.J. Watt. The Texans defensive end racked up 78 tackles and 20.5 sacks—second only to Justin Houston—along with five offensive touchdowns. His outstanding season earned him the Defensive Player of the Year award, and made him a front-runner for the league MVP (he became the first defensive player since 2008 to earn votes). So, behind the guy who could probably play every position on the field, who is the second-most valuable defensive player in the NFL? SI.com's staff makes their picks.

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Don Banks: Darrelle Revis, CB, New York Jets

The NFL has long worshipped at the altar of the sack specialist, but in this age of pass-happy offenses, the quarterback still wins far more often than the pass rushers do. And if you can’t disrupt the quarterback in the pocket, the far more effective approach to playing pass defense is to find one of the game’s few cornerbacks who can consistently win in coverage.

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A truly elite cornerback like Revis can influence an opponent’s strategy and force a quarterback to change the way he views the field. There might not be anything resembling a “shutdown’’ cover man in the league, but Revis impacts games by discouraging passers from testing him too often, in effect limiting a quarterback’s options and inducing him to avoid taking risks in his direction.

Did the Patriots win last year’s Super Bowl, after so many near-miss seasons in New England, just because they signed Revis in free agency? No, but he was the single most critical piece of their defensive upgrade last year, and his presence gave Bill Belichick a trump card to play with that he hasn’t had since the heyday of the Patriots’ defensive-fueled repeat Super Bowl champions of 2003-'04.

There’s a reason why teams keep lining up to pay Revis lavish sums of money. He’s the real deal. His presence is a difference-maker that elevates the entire defense around him. Even when you don’t notice him throughout the course of a game, that invisibility often translates to success, in that he has taken another star receiver out of the flow of the game.

Ben Eagle: Justin Houston, OLB, Kansas City Chiefs

If we're ignoring Watt, Houston is the obvious choice. Just look at his numbers from last season: a league-high 22 sacks (a half sack shy of Michael Strahan's all-time record), 68 tackles, four forced fumbles. In any other season, those stats earn you DPOY honors.

But he's more than just a pass-rusher. Houston logged 22 stops in run defense in 2014, a stat surpassed by just five other 3-4 outside linebackers, per Pro Football Focus. And he more than holds his own when asked to drop in coverage.

Was '14 a contract-year push by Houston? Perhaps. The fourth-year pro's previous career-high was just 11 sacks. Regardless of his motivation, Houston truly arrived last season, and it's hard to find a better all-around defender not named J.J. Watt.

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Doug Farrar: Earl Thomas, S, Seattle Seahawks

Since he joined the Seahawks as the second of their two first-round picks in 2010, Thomas has defined the NFL's best defense more than anybody else. Even guys like Richard Sherman and Michael Bennett, ultimate alpha dogs, will tell you that Thomas exudes a different level of intensity and demands a different level of play from himself, and that shows on the field every game. When Thomas entered the league, the Texas alum was considered by many to be a cornerback/safety hybrid with some tackling issues and occasionally reckless play. He's cleaned the issues up over time, and now, he's able to use his demon speed with pure accuracy and a total disregard for his own well-being.

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Watching him zoom around with guided-missile hits brings to mind the classic quote from former San Francisco 49ers guard Randy Cross about teammate Ronnie Lott: "He doesn't care about his own body. Why should he care about yours?"

The result is a player who makes it all go in Seattle. Without Thomas's rare ability to cover the entire field with angular awareness and track speed, the Legion of Boom secondary would not be able to cover as it does. Sherman can establish outside position on top receivers because Thomas is in the outfield in case something goes wrong. Fellow safety Kam Chancellor can alternate between enforcing in the box and moving out to deep coverage in a shorter area because Thomas's coverage span is as wide as anyone's in the NFL. And anyone who plays in that secondary learns very quickly that if you fall below a certain standard, it won't be Sherman or Chancellor who talk to you about it—it will be Thomas. Thomas is perhaps the team's most talented player, and he's mined his talent to the point where he's the team's most irreplaceable entity.

Bette Marston: Luke Kuechly, MLB, Carolina Pathers

The best defensive player in the league who isn't J.J. Watt, the 2014 defensive player of the year, has to be the 2013 defensive player of the year. (That's how it works, right?) In 2014, the third-year middle linebacker led the NFL with 153 tackles—his second time in his three years finishing No. 1 in tackles—and earned his second Pro Bowl nod. Kuechly's ability to identify the offensive play and make tackles all over the field is unparalleled, and he defended 13 passes, caused one fumble, recovered one fumble and made one interception during the regular season.

However, the most telling stats are those about the Panthers's defense as a whole. In 2011, before Kuechly was drafted, the Panthers' defense was ranked No. 28 in yards given up per game. In '12, the defense rose to No. 10, and has remained in the top 10 in the three years that Kuechly has been on the field for the Panthers. We can't say that rise is due to Kuechly alone, but the numbers don't lie.

Teammate Cam Newton recently became the NFL's newest $100 million man, and Kuechly's contract extension isn't far behind. Kuechly knows he's playing for money this season, and it's going to show on the field this year.

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Amy Parlapiano: Richard Sherman, CB, Seattle Seahawks

Once you remove J.J. Watt from contention, I don’t think there is another defensive player in the NFL who truly means as much to his team as Sherman does. He’d be the first to tell you that everyone is scared of him, and he’d be right. According to ProFootballFocus, he played 1,130 defensive snaps in the 2014 season, including the playoffs through the NFC Championship Game, and was targeted just 72 times. According to ProFootballFocus, in that same time frame, his opposing passer rating was 38.7 (Revis’s, by comparison, was 70.5.)

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The Seahawks’s entire style of play would be different without Sherman. He removes top receivers from games in a way that has only recently been rivaled by what Darrelle Revis did with the Jets in their first couple of years under Rex Ryan. Sherman is an island of his own, he is the leader of that Legion of Boom, and while the Seahawks have other excellent players around him, without him, that defense falls from excellent to merely good. With him, they’ve made it to two consecutive Super Bowls. And as long as he’s there, there’s always a legitimate chance for a third.

Eric Single: Ndamukong Suh, DT, Miami Dolphins

The contract doesn't lie. Suh, like Watt, is a regular recipient of a defender's ultimate compliment, as opposing offenses draw up double-teams and make constant note of where he is on the field before each snap. Coming from a spot on the defense that the casual fan's eyes rarely focus on, the suddenness of Suh's burst never loses its magnetism.

With stat categories that don't translate smoothly across positions, comparing the value of defensive players is pretty dependent on how highly you regard each level of the defense. The way I see it, Suh lines up too close to the ball to be avoided the way shutdown cornerbacks or even many edge rush specialists can be.

Suh's tackle and sack totals (47 and 10.5, respectively, between the 2014 regular season and playoffs) undersell how often teams worry about where he's lining up. The Lions held their opponents to just 69.3 rushing yards per game in 2014, finishing 10 yards clear of the next-closest team, and if the Dolphins' defense ascends to the league's top tier in '15, Suh will be inseparable from that success.