But will the reshuffling work?
"I don't know. You'll find out Sunday when you see all of us on the field at the same time," Chaney said Wednesday following the first practice in which the moves were implemented. "I like the change. I'm down for everything Juan and Coach Reid [are] doing."
Chaney said he preferred playing in the middle. Last season as a rookie, he started three games there in place of the injured Stewart Bradley, who was not offered a contract and wound up in Arizona. Chaney's first start came against the Giants when he tallied 16 tackles and forced a fumble. In the playoffs against the Packers, he notched 11 tackles and a forced fumble.
"This is the position I like to play," Chaney said. "I liked playing [strong-side], but I was just getting used to it."
Fokou played primarily strong-side his first two seasons with the Eagles, starting 15 games there. Matthews was in the middle at Oregon a year ago, but many projected him heading into the draft as an outside linebacker in a 4-3 scheme.
The Eagles drafted him in the fourth round and, despite the NFL lockout that cancelled offseason workouts, Castillo had Matthews as the starting middle linebacker by the first day of training camp.
He struggled through the preseason, though. Reid said therewould be some growing pains, but the pain was apparently too much to bear after the first two games. The Eagles' run defense ranked 30th in the league, allowing 146 yards a game. Of 55 opposing rushes, 18 were up the middle for average gain of 10.4 yards.
"It's not really different," Matthews said of the changes.
While the Eagles prefer to have their linebackers interchangeable, there are some very significant differences at the positions.
"I like to look at pretty much the whole offensive line to the fullback. Being a [middle linebacker] you can see all that," Chaney said. "At [strong-side] you can pretty much see only half the line."
Chaney admitted that he was surprised when he reported to training camp in late July and found out that he had been moved to strong-side. Castillo has said that strong-side was the more important linebacker position in his scheme and that he wanted Chaney there for his cover skills against tight ends.
But Chaney had trouble keeping up with Falcons tight end Tony Gonzalez on Sunday, although many have suffered the same fate against the future Hall of Famer. Fokou isn't as adept in coverage, but he won't be on the field on most passing downs.
Chaney said that he will continue to stay on the field in the nickel defense with either Matthews or Brian Rolle - and sometimes Keenan Clayton - playing alongside him. Chaney will also now take the headset from Matthews and make all the calls on defense.
Taking that chore away from the rookie could lighten his load.
"With [weak-side] he doesn't have to worry about making calls," Chaney said. "He did a good job. Out of all the rookie linebackers in the league he probably had the most pressure or responsibility on him."
The Eagles weren't the only NFL team to open the season with a rookie starting at middle linebacker. The Giants, however, were forced to turn to Greg Jones – who will start Sunday - after Jonathan Goff suffered a season-ending knee injury during the preseason.
Contact staff writer Jeff McLane at 215-854-4745, firstname.lastname@example.org or @Jeff_McLane on Twitter.