"We're trying to cut some things back and make it easier for the guys to understand what we want them to do," said cornerbacks coach Johnnie Lynn, who was introduced along with several new Eagles assistants.
Some around the team complained that McDermott's playbook was too intricate and that it overloaded the pupils. That was evident in the red zone - the Eagles had the worst red-zone defense in the NFL in 22 years - where defenders need to be more reactionary.
Obviously, this was one reason Andy Reid thought Castillo could make the transition to defense. For 13 years, his teaching methods with the Eagles' offense line emphasized the basics of blocking.
"We did things over and over and over till it became a muscle-memory deal," Castillo said. "That's my philosophy."
It was hard not to listen to the new cast of defensive coaches and not think that the changes were a referendum on McDermott, who coached under a tremendous amount of pressure, both circumstantial and self-applied.
While there are still legitimate questions about the talent and experience of the players McDermott was dealt, the 36-year-old made matters worse with how he delegated responsibilities.
"I think Sean was just a little tight. I think with Juan we're going to have a little more fun," said Mike Zordich, who was promoted from quality-control coach and put in charge of the safeties. "I think there's just going to be a little more balance in the room, and things are going to be spread out a little more."
They would have to be. Castillo hasn't schemed against an offense or play-called on defense since he coached Texas high school ball in the 1980s. So the entire burden on defense isn't necessarily going to fall on his shoulders.
And it starts up front with the acclaimed Jim Washburn - who left Tennessee, he said, because the Eagles have quarterbacks - tutoring the defensive line.
"If you just rush four all the time you'll get killed," Washburn said. "If you blitz all the time you'll get killed. If you rush three all the time you'll get killed. . . . You've got to do different things. It doesn't have to be complicated, though. . . . I think we want to let the players play."
One example of letting the players play, Washburn noted, was not having his best pass rusher, Trent Cole, drop into pass coverage as he did on occasion last season. The 61-year-old is also known for lining his ends, particularly his right end, more outside the tackles and having them rush up field.
This slight difference will affect the back seven, particularly the linebackers. If Cole, for instance, runs up field, the quarterback has more room to step up if the end is blocked, and the strong-side linebacker will have to be there as a safety net.
But scheming, Washburn said, isn't his forte.
"I'm a trench dude," he said. "I can help out with the crunch stuff, and I've got some ideas. But that's not my deal. I tried to be a coordinator one time, but I sucked."
That's where Lynn comes in. The 54-year-old has been a coordinator, spending two years with the Giants in that post. He said he was not contacted for the cornerbacks coaching job until after Castillo was named.
The two have known each other since the early 1990s, when Castillo was an intern and Lynn the secondary coach for Tampa Bay. Even then, Lynn said, Castillo was known for his energy and fiery personality. The Eagles are banking on the defense adopting the demeanor of its new coordinator.
"I think when [former defensive coordinator] Jim Johnson was here they had his personality," Castillo said. "I felt with my linemen that we were aggressive, that we were tough, that we were physical, that we finished everything, and that we tried to choke people. You know, be physical."
Allen time line. Nate Allen, who ruptured the patellar tendon in his knee in December, said that he would be "100 percent" when training camp starts in late July.
The free safety, though, may have to find other trainers to help him through his rehabilitation if there is an NFL lockout in March. If the owners shut the players out, Allen, who would be barred from the team's facilities, said that he would continue his workouts in Arizona.
Contact staff writer Jeff McLane at 215-854-4745 or firstname.lastname@example.org. Follow him on Twitter at www.twitter.com/Jeff_McLane.