Fletcher Cox broke the 30-year-old threshold in December and is playing his first full season as a defender no longer in his 20s.
The numbers would seem to indicate Father Time is gaining ground on the six-time Pro Bowler. Or maybe, it's simply a matter of a scheme change that isn't exactly friendly to Cox.
"I could be better. I know I can be better," Cox said on Wednesday, via NBC Sports Philadelphia. "That's a problem I have to fix. Embrace whatever we're doing and make the best of it."
The 2021 season is Philadelphia's first under new defensive coordinator Jonathan Gannon, who has expanded Cox's responsibilities, including playing in a couple of different alignments. Cox has recorded just five tackles and has gone four games without a sack after combining to record 81 tackles and 10 sacks combined between 2019 and 2020.
"Sometimes I play in the 3-technique, sometimes I play in the 4i," Cox said. "It's just one of them things where it's hard to get settled in, in a game when you're playing so many positions and doing so many things."
Alignments matter because of how they affect how defenders fit blocks against the run and maintain gap integrity -- essentially, keeping leverage against blockers in the space between them, cutting off running lanes for opposing backs. They also affect how often Cox might see multiple blockers in both the run and pass.
Cox has spent the majority of his career playing the 3 technique -- aligned over the outside shoulder of the guard -- and has rattled off a half-dozen seasons worthy of Pro Bowl selection. Now, he's also expanding his job to include matchups over the inside shoulder of the tackle, which creates distance between Cox and the interior of the line of scrimmage.
Teams can choose to run away from Cox in these instances with slightly more ease than when he's in a 3 technique. Guards can also receive more help from tackles when he's in a 4i.
So far, it's limited Cox's production, begging the question: Is Cox regressing as he ages, or is he playing in a scheme that doesn't take advantage of his strengths?
"We do a lot of different things," he said. "All I can do is prepare for it week in and week out."
For what it's worth, Cox has made a difference in at least one game, snagging a Dak Prescott fumble for a defensive touchdown in Week 3. He just hasn't been the game-wrecker he's been for most of his career.
"I would say Fletch is doing a good job right now," Gannon said. "Again people know that we play with Fletcher Cox, so they do certain things that you typically don't see on tape. What we get, certain teams do not get because of our personnel.
"So it's always a constant, 'Hey, let's try to find ways to, free up Fletch or get Fletch going.' But I thought -- he's playing good. And, again, the production -- guys, we're four weeks through, the production will come. I'm not worried about the production from Fletch."
Might we see a change from Gannon to get Cox going? At this point, it doesn't seem likely. Teammate Javon Hargrave has been a menace along the interior this season, and the Eagles rank 10th in QB pressure percentage (30.2 percent) despite only blitzing on 12.4 percent of passing downs.
They're also currently 31st in the NFL against the run -- an effort Cox could undoubtedly help improve if put in the right position.
For now, it will remain business as usual for the Eagles, even if it's not difficult to sense Cox's frustration.
"Whatever they ask me to do, man," Cox said. "I'm going to do it to my best ability. I'm going to be a pro about it, be very professional about it, go out and make the best of it."'
The Eagles travel to Charlotte to take on the Panthers this weekend.
