There are days, and Tuesday was one of them, when Fletcher Cox wakes with the memory of his brother filling his thoughts, and he knows that Shaddrick Cox will follow him through every step of the day.

"He's been on my mind heavy since this morning. It's been a sad day for me," Cox said. "I think about him a lot."

The memory doesn't get in the way of the work, of course, and Fletcher Cox is considered the best player on the strongest unit of the Eagles, but when his older brother and mentor died of a heart attack in January, a little bit of the younger brother went with him.

This time of the month, around the date when Shaddrick died and the family gathered in Yazoo City, Miss., for his services, is the most difficult. Without even thinking about it, Fletcher Cox has the feeling come over him.

"It's every month close to that date," Cox said "People ask me what's wrong and I tell them I'm thinking about it. They tell me to try and move on."

Fletcher Cox is a great football player, physically made for the game, but it was his older brother who pushed him to work hard enough to make it a career and to find his way out of Mississippi to a more comfortable life. Cox owes his brother and he pays something back to his memory with every repetition on the field.

"He's a great football player," said nose tackle Benny Logan, who along with defensive end Cedric Thornton and Cox, forms the front wall of the Eagles' 3-4 defense. "Anybody can be good. He puts in work to be great. He doesn't do a lot of talking. He just goes out and puts in the work. He shows up every time on the field and he dominates."

The Eagles moved up three spots to select Cox with the 12th pick in the 2012 draft and he played tackle as a rookie in the team's final season as a 4-3 defense. Transitioning to end under new defensive coordinator Bill Davis in 2013, Cox adjusted to the position change quickly. By last season, he was among the best in the league.

"It wasn't easy. It was a learning curve," Cox said. "It was something I'd never done. It was all different for me, but I had to soak it in. I was here and that's the defense we're going to play. I had to get good at it."

In the 3-4, the down linemen are often the ones who spring the trap, but not the ones who get the mouse. They collapse the line, stuff the run holes, and make it possible for others, often the outside linebackers, to collect the sacks or the hurries that lead to interceptions.

"It comes from being a selfless teammate," Cox said. "You don't get all the fame the other guys get. We want to be a grimy group of guys who come in and play nasty the whole game."

The Eagles picked up the fifth-year option on Cox's contract for 2016, but he could become a free agent after that, unless he and the team agree to a longer-term deal in the interim. Handling that situation will be an interesting indication of what Chip Kelly, who controls the whole roster, really values. On Tuesday, he said Cox's value is unquestioned.

"I think Fletch can play any position on the defensive line in any system in the National Football League. He could be a nose, he could be a three-technique, he could be a one-technique, he could be a five-technique in a 4-3, he could be a four-technique," Kelly said, rattling off nearly the entire list of NFL defensive line assignments. "I think anybody out there would take his size, height, and weight parameters for what he's doing."

At 6-foot-4, Cox is on the low end of Kelly's optimal height for the position, but he has an exceptional wingspan, as does the 6-4 Thornton, and a talent package that keeps him on the field. Cox played 921 snaps in 2014, 80 percent of the defensive total, and far more than any other lineman. Thornton's 640 snaps were second. Only outside linebacker Connor Barwin (1,007) had more snaps among the 15 players who formed the front seven last season.

"Fletcher's the good guy. I think he's one of the best in the league at doing what he's doing, but the thing is he doesn't go out and brag and boast," Logan said. "If you dominate, though, people start talking about you."

That is what is happening now, and the talk can be traced all the way back to Yazoo City and help from a brother who put him on this road. The road is bumpier without him and there are days that are harder than others. Tuesday was one of those and then the football came along and Fletcher Cox was able to lose himself in that once again.

"It's how you approach things," he said. "If you approach them the right way, anything is possible."

@bobfordsports