Fletcher Cox's first six years in the NFL put him in the class of the NFL's best defensive players. By the end of the 2018 season, Cox wants to be  in a class of his own.

Cox now has a Super Bowl, three Pro Bowl invitations, all-pro honors, and a $103 million contract on his resume. Next on the checklist, as Cox described in the spring, is being named defensive player of the year.

"What's it going to take?" Cox said. "Just going to take me continuing to be dominant."

It's going to take more than what he has exhibited in recent seasons. Five defensive linemen have won the award in the last six years. They all recorded double-digit sacks. Los Angeles' Aaron Donald won with 11 sacks last season. Houston's JJ Watt averaged 19.5 sacks during his three seasons winning the award.

Cox's career high was 9.5 sacks in 2015. He had 5.5 sacks last season. He has 13 total sacks in 33 regular-season games playing in Jim Schwartz's defense, including the playoffs. As well as Cox has performed in an Eagles uniform, he has never reached prolific sack production. So he would probably need a career season to distinguish himself among elite company this season.

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"I've had a bunch of chances for double-digit sacks," Cox said. "I've just got to finish on the quarterback more. Those sacks that I missed – could have had him, but he slipped out of my arms."

Schwartz offered a different spin. An outstanding season from Cox might not be reflected in the sack total, and the defensive coordinator thinks there are enough metrics and analytics that can be used to see the effectiveness of a player beyond looking at one column on his stat sheet.

"There are plenty of times that you can do everything right and not get the sack," Schwartz said. "You can have a great rush, get the quarterback, and the quarterback be going to the ground and throw the ball away. Flag comes out, it's intentional grounding. The ball is at that spot with loss of down, but guess who didn't get the sack registered? The defensive lineman who earned it.I think that we try to keep our eye on just being efficient, playing well, being productive, and productive doesn't always mean that you're actually getting the sack."

This is an argument Cox would make, too. There's so much that goes into a defensive lineman's job. The attention Cox draws from offensive linemen makes the defensive linemen around him better. When he causes penetration, the quarterback cannot step up into the pocket. If the quarterback must pass quicker, it helps the cornerbacks. If the quarterback must roll out or back-peddle because Cox is coming, it helps the edge rushers. And that's only on passing downs. The way he can disrupt the running game was a big reason the Eagles had the NFL's top-ranked rush defense last season.

"It's 2018, and people look at it way differently," Cox said. "Sack numbers are good, but are you effective on first and second downs, not just passing downs? Are you really making a big difference in the game? That's the biggest thing for me."

Inside the Eagles building, the belief is that Cox's value cannot be measured by sacks alone. He made  impact plays throughout the season that helped change games. He recovered a fumble in Week 16 to set up a game-tying field goal. He had a sack on a two-point conversion in Week 15 to preserve a narrow lead. He forced an errant pass in Week 6 that was intercepted and helped the Eagles tie the score. He sealed a Week 1 victory when he recovered a fumble and returned it for a touchdown.

"I think at the end of the day, you've got to look at the best players on the best teams," defensive line coach Chris Wilson said. "A lot is obviously equated to sacks. And taking nothing away from any player in this league, but I look at, are you the most complete player? A guy who can play the run, a guy who keeps his mistakes minimal. A guy who makes everybody in the building better because he's in the building. And I think Fletcher has the ability to be all of those."

There's also the issue of the Eagles' defensive line rotation. Cox played 76 percent of the defensive snaps in 2016 and 59 percent of the snaps in 2017 while missing two games. The playing time dipped from the previous two years, when he played at least 80 percent of the defensive snaps and averaged 13 more snaps per game.

But come playoff time, the Eagles relied on Cox more. Cox took 86 percent of the defensive snaps in the postseason. His performance in a 15-10 win over the Atlanta Falcons in the divisional round of the playoffs while playing 90 percent of the snaps might have been his best in an Eagles uniform.

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Still, there are areas Cox can improve on in 2018. He would be the first tell you he must finish on the quarterback and go for the ball and not just the hit. Cox remembered three times when he pummeled the quarterback and the pass was still delivered at the last moment for a completion. And for someone who often says his objective is to "dominate," he can play at an elite level more consistently. Cox's baseline is higher than many players' best, but if he can play at his raised level every week, the Eagles would have their best version of Cox yet.

"With Fletch we're talking about shades of gray," Schwartz said. "Some players you're talking about significant steps they need to take. He's not far. I think you could probably pick out eight games where he played at that level anyway."

Cox became a prominent player for the Eagles at 22. He inked a nine-digit contract at 25. The excitement about him in the organization has always been his potential as much as his production. At 27, Cox is now in the prime of his career.

"I ain't old, man!" Cox countered.

Not old, but if there's a time for him to have a season distinguished among the league's top defensive players, it's this year. Warren Sapp and Dana Stubblefield won the award as 4-3 defensive tackles in the 1990s around the same age.

"It's Year 7 for me," Cox said. "I'm not viewed any more as a young guy. I've continued to grow each year and show I can still be dominant in this league."