At this time last year, Fletcher Cox and Mychal Kendricks were promising rookies brought in to upgrade an underachieving Eagles defense. Second-round pick Kendricks was a starter at outside linebacker from his first practice. First-rounder Cox found a spot in the crowded defensive line rotation.

Their coordinator was dismissed during their rookie season and coach Andy Reid was gone at the end. A whole new system is in place for their second season, but what remains are the team's plans for Cox and Kendricks, two cornerstones for the defense going forward.

"We're not first and second draft picks anymore - we're core players," Kendricks said. "There's no need to talk about first and second round."

There are position battles throughout the defense, which has been reworked from a 4-3 to a 3-4 and includes major personnel changes. But barring injury, Cox will start on the end in the three-man defensive line and Kendricks will start at inside linebacker.

Both will be 22 on opening day, the team's youngest expected starters on offense and defense. They're both younger than first-round pick Lane Johnson.

Both have noticed a marked difference between their first and second seasons. Kendricks remembered the veterans telling him how much easier the second season is compared with the first, and he is "astounded" by how accurate they were.

"The speed of the game has completely slowed down to the point that I'm thinking a whole lot more faster, seeing things a whole lot more clear," Kendricks said. "Just the general understanding of the game, of the way the NFL game works."

Cox, who takes pride in being a quick learner, said he was just trying to acclimate to the rhythm of the NFL last season. This year, he said he knows what to expect.

His best production came after he entered the starting lineup for his final seven games of the season, when he recorded 41/2 of his 51/2 sacks. That was an encouraging sign, but Cox expects more.

"I never say I'm that guy - I always do that to humble myself," Cox said. "I never think I've arrived. That's when you stop focusing on the main things."

The Eagles' scheme change is not dramatic for either player. Kendricks played in the 3-4 during two of his seasons at California, so he's familiar with the principles of the defense.

The Eagles moved Kendricks between outside linebacker spots last season, but he is purely an inside linebacker in the new defense.

Chip Kelly coached against Kendricks in college and had a glimpse of his skills.

"Chip hated me, probably," Kendricks said. "I killed him, straight up."