Rookie nose tackle Damion Square was faced with a difficult decision that would alter his future.

It was April 2013. Square was an integral component of three BCS National Championship teams at the University of Alabama. However, that wasn't enough to merit a selection in any of the seven rounds of the NFL Draft. Square was free to sign with any NFL team, but no matter which team he chose he would come in on the bottom of the totem pole and have to work his way up to earn a roster spot.

Square recalled a 10-minute conversation he had with defensive line coach/assistant head coach Jerry Azzinaro at the NFL's Scouting Combine in February.

"He's a guy who stuck with me. He knew a lot about me," Square said. "I could tell from the conversation that he had watched me thoroughly on film. I remember the impact that he had in those 10 minutes."

By showing a little bit of respect, the Eagles landed Square's services and the rookie free agent not only made the final 53- man roster, but has found a way into the defensive line rotation.

The Eagles defense has been a crucial part of the team's turnaround in the second half of the season. A successful defense begins up front, where the Eagles boast six talented linemen who are all young. The oldest member is defensive end Clifton Geathers, who just turned 26 years old on December 11. The three starters — ends Fletcher Cox and Cedric Thornton and nose tackle Bennie Logan — and the other two reserves - Square and defensive end Vinny Curry are all 25 years old or younger. "When we went into the season, we talked about the defense growing and getting used to a scheme change with a lot of younger players. They are doing a good job of getting better and growing as a unit," said general manager Howie Roseman.

The men who have been entrusted to teach and develop these young linemen are Azzinaro and assistant defensive line coach Erik Chinander.

"He's a guy who brings the best out of you. He gives you a pat on the back when he needs to, but at the same time he knows how to encourage you to get better," Square said of Azzinaro. "He never believes we're as good as we're going to be.

You come across guys who get to a certain level and they stop coaching for whatever reason. He finds something to talk about everyday when we're in that room."

Azzinaro was head coach Chip Kelly's right-hand man at Oregon where he served as the Ducks defensive line coach from 2009-12. He explained that his biggest job as a coach is being a teacher  first.

"Good coaches focus on the same things — winning the day and making the most out of every day," Azzinaro said. "It's a day-to-day- type job. You have to win today and then move on to tomorrow.

"I think all people, young and old, want to know why they are doing something. When they know why it makes change simpler. They want you to help make them better."

Azzinaro gets a lot of the praise for the rapid development of the young defensive line, but the players credit Chinander as well. Chinander was an offensive lineman at Iowa who served as a graduate assistant under Kelly for the past two seasons before coming to Philadelphia.

"When we get together as a position group on the field, we split up between the two coaches and Coach Chins will teach us and show us different techniques. He's been an important part of our development," said Cox.

THE FIRST-ROUND PICK

Cox was the Eagles' first-round pick in 2012 and made an immediate impact by notching 5.5 sacks, which tied for the team lead.

He thrived as a defensive tackle. The question was whether Cox's talents would be neutralized in the switch from a 4-3 to a 3-4 scheme.

"Strip to change, strip to change," Cox said echoing the remarks from his coaches. "You've got to be willing to do that. Not everyone is willing. It'll take you a long way."

Cox was not afraid of change and immediately began doing what the coaches asked him. Logan looks up to Cox as a "role model." Cox has no issue with being the leader. Even though he's only in his second year, he has the most starting experience among all of the linemen. With how young the position group is, Cox understands that he still has a lot to learn.

"I think it's a good thing, but I learn from those guys too," Cox said.

Even in his new role, Cox remains proficient in getting after the quarterback as he ranks among the league leaders at his position in quarterback hurries, according to Pro Football Focus. Cox credits the coaches' commitment to teaching the proper fundamentals as the biggest reason for his successful transition to the new defense.

"That's the most important thing. It's the technique, all of the little things. You've got a group of guys willing to learn," Cox said. "You've got a group of guys who are going to play hard for four quarters and that's how you want to be known."

THE ROOKIE

On October 29, the Eagles completed their full commitment to the youth movement along the defensive line when they traded nose tackle Isaac Sopoaga to the New England Patriots. In Sopoaga's place, the Eagles inserted Logan, who has thrived since the promotion.

"I just told him relax and be Bennie Logan," Cox said. "This wasn't his first time playing football. He's been playing football all of his life."

At LSU, Logan wore No. 18, which was a tradition for a player who possesses a selfless attitude. Like Cox, Logan was not used to playing in a 3-4 scheme, but he was not fazed by the challenge after he was drafted by the Eagles.

"You're going to make mistakes, but I know those guys are there to help me," Logan said. "Everybody is held accountable for their own mistakes."

The difference that Logan notices with his current coaching staff is the consistent attention to detail. As the season wore on, the work on the little aspects of the game didn't waver.

"They do a great job of getting us ready. We hit on technique every day. It's not one day on, one  day off," Logan said. "As the season goes on, you tend to lose technique, fundamentals. The whole  coaching staff makes sure that technique is polished up and corrected." Cox said that Logan's willingness to learn has helped him adapt to the speed of the NFL. "Bennie likes to have fun, but he's serious when he needs to be," Cox said. "He coachable. He's always willing to learn."

THE UNDRAFTED ONE

The defensive lineman who has performed the best this season is the one with the lowest pedigree. Thornton, a former rookie free agent, has thrived in the Eagles' new defense. Logan sees a work ethic that is "second to none" from the 6-foot-4, 309-pound Thornton.

Unlike his fellow starters, Thornton has felt the sting of being released. He also has a family with two children — son, Cedric, and daughter, Kaylei — to provide for.

"You're only as good as your last game. If I come out this game and stink it up, which I don't think God will allow me to, then you'll be telling me how bad I played," Thornton said. "It's all about consistency, so I'm just trying to be consistent."

The Eagles' investment in the defensive line has paid dividends and will do so for years to come. Azzinaro and Chinander have boiled down the game of football to its most essential basics and it's those tenets which players like Thornton have taken to heart.

"Focus on the man in front of you," Thornton said. "Try to beat the man in front of you and rely on other guys to do their job."