The five fourth-quarter leads the Eagles coughed up in the first nine games weren't solely the fault of the defense. But Castillo and his unit were most responsible for surrendering those leads. Some came in brutal fashion as opposing offensive coordinators outclassed the former offensive line coach.
And what exactly was Castillo's defensive philosophy? Everything the defense did revolved around Jim Washburn's wide-nine scheme up front, but the back seven was a convoluted mess of zone defenses.
But you know what? Something clicked over the final four games. Everything seemed to come together.
Compared to the first 12 games, the defense improved statistically in every category in the final four games - points (23.5 a game to 11.5); first downs (19 a game to 15.3); third-down conversion rate (38 percent to 29.5); yards per play (5.7 to 4.1); completion percentage (59.2 to 55.2); turnovers (1.3 a game to 2); and red-zone efficiency (70.6 percent to 30.8) being the most prominent.
There could be a bit of fool's gold in thinking Castillo's defense will be just as good this season. The Eagles had little to play for in the last four weeks. And only one of the three quarterbacks (the New York Jets' Mark Sanchez) they faced over that stretch will be a starter this year.
But just in case, Andy Reid hired Todd Bowles to head his defensive backs and to assist Castillo. Some believe Bowles, Miami's interim coach late last season, is Reid's break-in-case-of-emergency coordinator. And maybe he is.
But if the defense is as stout as it was last December, when it was statistically the best in the NFL, both Castillo and Reid can rest a little easier.
- Jeff McLane
2 DeMeco Ryans solves the middle linebacker situation.
In six short months, DeMeco Ryans has gone from savior to bust, and the Eagles have yet to play a meaningful game.
That's how it works in Philadelphia, where football is king, the middle linebacker position is revered, and the preseason is overvalued.
In approximately four quarters of football over three preseason games, Ryans did little to suggest that he will dominate on defense this season. He looked tentative. He appeared a whole notch slower than rookie strong-side linebacker Mychal Kendricks, who glided from sideline to sideline.
Ryans' game, however, has never been about pure speed. He's always been characterized as an average runner. His strength is reading offenses, knowing where to be, and cutting down the angles.
And Ryans' preseason tentativeness can be chalked up to the 28-year-old's saving his energy and slowly preparing for when the games really count. He is patient. When asked about the lofty expectations, Ryans smiles and, with his Alabama drawl, responds: "Aw, it'll be all right."
His presence alone should be an upgrade. Last season, rookie Casey Matthews was thrust into the spotlight. Still can't figure whose bright idea that was. Jamar Chaney fared better, but he did not commandeer the defense, one that was gashed up the middle.
One of Reid's oversights from last season was not acquiring linebackers equipped to handle playing behind Washburn's wide-nine defensive line. The gaps were wider, in many cases, and the blockers came at linebackers quicker because the linemen had a pass-rush-first mentality.
The coach admitted this mistake when he traded for Ryans, a two-time Pro Bowler, in mid-March. A week later at the owners meetings, Reid summed up his error in two words: "I goofed."
Ryans is not a slam dunk by any means. He ruptured his Achilles tendon in October 2010. He was not 100 percent last season, and he played less as one of two inside linebackers in the Texans' 3-4 scheme.
The Eagles and Ryans say his tendon is healed. They say the move back into the middle will correct his issues from a year ago.
If so, it will give Reid his first legitimate middle linebacker since Jeremiah Trotter.
- Jeff McLane
3 DeSean Jackson and Jeremy Maclin become an elite wide receiver tandem.
The Eagles are pinning a portion of their offensive hopes on the development of DeSean Jackson and Jeremy Maclin, who are now NFL veterans and expected to contribute like one of the NFL's top receiving duos. In 2011, three NFL teams had two 1,000-yard receivers. The Eagles have never had two achieve that feat in the same season. This could be the year that changes.
Jackson topped 1,000 yards in 2010 and 2011 before his production declined in 2012 while he was distracted by his desire for a new contract. Maclin endured health issues at the beginning of the season and led the team with 859 receiving yards, but he has fallen shy of 1,000 yards in each of his three NFL seasons.
The Eagles invested major money in Jackson and could do the same for Maclin, but the two need to play to that potential first.
There are indications that could happen. Jackson is satisfied this season, playing with a clearer mind and the security of knowing injuries will not affect his bank account. Maclin is healthier this season and has the opportunity to earn a lucrative contract considering his age (24) and potential (he was the No. 19 pick in the 2009 NFL draft). The possible deterrents to the two each reaching 1,000 yards is the Eagles' propensity to spread the ball around, and Michael Vick's injury history. Tight end Brent Celek, running back LeSean McCoy, and slot receiver Jason Avant all will swallow catches. But the ball is spread around in New England, Green Bay, New Orleans, and New York, too, and those teams have strong pass catchers. The key in all four offenses is the quarterback play. If Vick stays healthy and Jackson and Maclin play to their capabilities, the Eagles will have one of the NFL's elite receiving duos. - Zach Berman
4 The defensive line helps the Eagles lead the NFL in sacks.
The Eagles tied the NFL lead in sacks last season with 50, and the defensive line is further bolstered this season. Jason Babin and Trent Cole, both of whom reached double digits in 2011, are elite edge rushers. The Eagles also benefit from the emerging Phillip Hunt, steady Darryl Tapp, and Brandon Graham, a 2010 first-round pick who is finally healthy. This does not even factor in the defensive tackles, including starters Cullen Jenkins and Derek Landri, and first-round pick Fletcher Cox. It is also the second year playing in Washburn's system, which could further enhance the Eagles' sack totals.
Washburn's line is built on rotating players in and out to keep them fresher than the opposing offensive line. Castillo likes to say the Eagles have eight starters on the defensive line, and all the active defensive linemen take snaps throughout the game.
"It's great coming off the field and seeing someone else come on the field who you know is just as good a pass rusher, maybe even better pass rusher, as you," Hunt said after the third preseason game.
Considering the talent the Eagles have on the defensive line and a scheme designed to pressure the quarterback - even at the detriment of the rush defense, sometimes - the Eagles could realistically lead the NFL in sacks. The NFC East does not feature strong offensive lines, either, which could also be a catalyst. And the NFL has never been more pass happy than it is now. It might be too ambitious to set the NFL record of 72 sacks reached by the Chicago Bears in 1984, but this year's group will try to get close.
- Zach Berman
5 Nnamdi Asomugha becomes the dominating cornerback the Eagles thought they signed.
It is unlikely Asomugha will be the cornerback he was in Oakland the five seasons before he came to Philadelphia.
That is not to say that he can't be just as good.
But Asomugha is not expected to exclusively play the man-to-man, press-cover defense here that made him such a feared cornerback with the Raiders. He will do more of that than he did last year when he played opposite Asante Samuel, who preferred to play off receivers. But the 6-foot-2, 210-pound corner still will play some zone. And he still occasionally will slide inside to cover tight ends.
Asomugha has repeatedly said he wants to test himself and try new things. Last season he was tested as much as he had been from 2007 to '10. He was targeted 41 times, only slightly more than the average of 34 times quarterbacks threw in his direction in the previous four seasons.
The completion percentage wasn't even that much worse. But Asomugha did surrender four touchdown passes - more than double what he allowed in Oakland over that span.
He biggest struggles came after receivers caught balls or when he played in the slot and was asked to help stop the run. Asomugha whiffed on 23 percent of his tackle attempts last season, according to ProFootballFocus, second worst among cornerbacks in the NFL.
When the Eagles signed Asomugha last July he was the prized acquisition in free agency. It seems now that lost in the backslapping after the blockbuster move was a cogent plan for how he would fit in schematically.
And now Asomugha is 31 years old. The Eagles got rid of Samuel in April because he was no longer a fit and seemingly in decline. Could they have gotten rid of the wrong 31-year-old? Probably not. If Asomugha and his counterpart, Dominique Rodgers-Cromartie, play near their capabilities, opposing receivers will have trouble getting open on the outside.
And Reid will have his shutdown corners in case his vaunted linemen can't get to the quarterback. - Jeff McLane
6 The Eagles adequately replace Jason Peters at left tackle.
This is a 330-pound if, and it's one that is imperative for the Eagles' offense. Jason Peters was strong and steady at left tackle last season and was a major contributor to McCoy's outstanding season. But two Achilles injuries during the offseason almost assuredly will sideline Peters this season - Reid mentioned there's a "slim" chance Peters returns - but in all likelihood, the Eagles will rely on King Dunlap.
Dunlap was the surprise choice for Peters' replacement. The Eagles signed Demetress Bell, who was Peters' replacement in Buffalo, to fill in for Peters in Philadelphia. But Bell was disappointing during training camp and the preseason, prompting the Eagles to turn to Dunlap.
As a key backup, Dunlap started seven games during the last three seasons. But that was in a reserve role, and never with the expectation of being responsible for the left side of the line.
"He's got a long road here to go this season and staying healthy and doing all of those things and playing aggressive football week in and week out," Reid said. "He hasn't had to do that at this level, but you have to give him credit for the battle that he's been in here with Demetress."
The left tackle is less important in Philadelphia than it is elsewhere because Vick is lefthanded, so the left tackle does not protect the quarterback's blind side. But he's still protecting the right defensive end/outside linebacker, which is often the opposing team's best pass rusher. In the NFC East, Dunlap will be charged with blocking the Giants' Jason Pierre-Paul, the Cowboys' DeMarcus Ware, and the Redskins' Brian Orakpo. If he can be an adequate replacement for Peters, the Eagles' offense will function as hoped. If Dunlap struggles, the offense could be in trouble. - Zach Berman
7 Rookies solidify the return game.
There have been seasons in which the Eagles' return game seemed like an afterthought. Reid would gather his skill players and figure one had to be competent enough to handle the job of either kick or punt returner, or both. Often, they were not.
But there were seasons when the Eagles were among the best in the league using Reid's method, especially early in his tenure with the team.
Recently, though, the Eagles haven't been as consistent in both regards. Jackson made the punt-return game a lethal weapon for three seasons, but last season, for whatever reason, the wide receiver wasn't as explosive. The Eagles average a fifth-worst-in-the-NFL 7.1 yards per punt return.
They were even worse in kick returns, averaging a second-to-last 20.9 yards. Rookie Dion Lewis handled the majority of kicks, but he had never done the job before, and it showed.
Reid, however, made a concerted effort this offseason to upgrade at both spots. The most significant addition was Brandon Boykin. The Eagles drafted the Georgia star in the fourth round with the idea that he would be the slot cornerback of the future. The future is now because Boykin beat out incumbent Joselio Hanson for that spot.
But the Eagles immediately touted his skills as a returner. Boykin set school records in kickoff-return yardage and touchdowns. He also occasionally handled punts. But the Eagles brought Boykin in to be their kick returner, and that is where he will start. During the preseason, he averaged 25.6 yards on nine returns.
At the punt-returner spot, the Eagles brought in a host of candidates to try out for the role. Undrafted rookie Damaris Johnson won it. Johnson, like Boykin, did everything at Tulsa. But he will specialize in returning punts here.
Johnson occasionally looked dazzling during the preseason. He averaged 8.9 yards on 10 returns. But he fumbled one - that he recovered - and bobbled another. So there is some concern with Johnson. If the rookie struggles, Reid can always go back to Jackson.
But this is one area in which the Eagles should improve this season. - Jeff McLane