Last year, Eagles defenders understood only a fraction of their playbook. This year, they understand it well enough to make their own interpretations of it.

Defensive coordinator Juan Castillo has been frank about the mistakes of last season, when the Eagles tried to integrate five new starters and implement a whole new scheme, with all new coaches, without minicamps or OTAs, with free agents such as Nnamdi Asomugha unavailable for the first week of training camp because of collective-bargaining issues. "Last year, it was a new system," Castillo said after the Eagles' 24-23 victory over the Ravens on Sunday. "It took us halfway through the season … let's not even talk about last year."

Castillo's defense looks much better than the unit that kept getting gauged for big runs and easy completions at the start of last season. The Eagles completely shut down the Browns' offense in a 17-16 win in the season-opener, with 10 of the Browns points coming directly from turnovers. Sunday's effort against a better offense was even more impressive and, as in the Browns game, the final score was a little misleading: Nine Ravens points came off field goals of 56, 51 and 48 yards.

Castillo has admitted several times that he had to rush to implement his defense last year, and players started the season uncomfortable with many of the concepts. During training camp, Castillo stressed the importance of defenders learning to play together in the system. "We didn't have the OTAs, so they didn't get to be around each other," he said in August. "A lot of times, in football, it's like: 'I know what he's doing because we've played together, we've been together on the field, spent a lot of reps.'"

This year, the defenders are not only more comfortable with each other, but confident enough in the system to make their own decisions. The Eagles' defense adjusted to the Ravens' strategy of trying to isolate tight ends against safeties in the open field on Sunday. But Castillo said that he was not the one who made the adjustments: The safeties themselves made the change.

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Figure 1 shows a typical Ravens play from early in Sunday's game. The Ravens have two fast tight ends in Dennis Pitta (88) and Ed Dickson (84), and their new no-huddle offense is designed to create mismatches by forcing defenses to keep their base personnel on the field, leaving one or both tight ends in coverage against slower linebackers or smaller safeties. Pitta is split out wide right on this play, with Dickson bunched on the left between dangerous receivers Torrey Smith (82) and Anquan Boldin (81).

With so much Ravens firepower on the left, the Eagles have no choice but to leave Kurt Coleman (42) in man coverage against Pitta. Coleman does not even have safety help, so he leaves a seven-yard cushion between himself and the tight end. This coverage creates an easy read and throw for Joe Flacco (5). Pitta runs a quick slant, Flacco takes a three-step drop and fires, and all Coleman can do is contain the play for an eight-yard gain.

Flacco completed five passes for 45 yards to Dickson and Pitta in the first half, often taking advantage of soft coverage by a safety when one of the tight ends was split wide or in the slot. In the second half, the coverage by the Eagles' safeties was not nearly as soft.

Figure 2 shows the Ravens facing third-and-two in the third quarter. Pitta and Dickson are lined up on the left side of the formation, but instead of facing Coleman, Pitta must now deal with physical cornerback Asomugha (24). Dickson is covered by safety Nate Allen (29), but what looks like a cushion before the snap disappears as Allen creeps toward the line.

Asomugha and Allen jam the tight ends. Hard. Asomugha actually knocks Pitta to the ground. Allen nails Dickson and stays tied up with him down the field; in other circumstances (a world with competent referees), Allen might have been flagged for illegal contact, but he gets away with a lot of manhandling on this play. A proper jam at the line both delays and redirects the receiver, throwing off the timing of the passing play. That's what happens here, as Flacco overthrows the harassed Dickson.

Figure 3 shows a similar defensive strategy in the final minutes of the fourth quarter. Dickson is now "flexed" in a three-receiver set. Allen is again in man coverage, and this time he is right at the line of scrimmage. Allen tries to jam Dickson, but it is not the wallop he delivered in Figure 2; Dickson sidesteps the safety after a slight shove. But a little redirection goes a long way when the offense is trying to execute timing routes. Flacco, who has taken some hits and appears to be rushing his reads at this point in the game, once again overthrows his tight end, who is a yard away and a split-second behind the spot he would have reached had he released from the line cleanly.

Taking Initiative: Jamming the Ravens' tight ends at the line more often in the second half was the right call. "The safeties took it upon themselves to challenge those receivers," Castillo said. "Sometimes, you don't know why they spread out a guy. Once you figure out what they are trying to do, then you adjust. That's what our safeties did."

Most NFL coaches are control freaks, and "freelancing" is a dirty word for most defensive coordinators. Allen and Coleman were not free to do whatever the heck they wanted in coverage, but they did have the latitude to make a few adjustments on their own. That kind of freedom can turn into chaos when defenders are not comfortable with their roles or each other's styles, which is exactly what happened last year. This year, with fewer new faces, a full offseason of minicamps, and everyone (including Castillo, a converted offensive line coach in his second season as defensive coordinator) more comfortable with his role in the system, there are fewer mistakes, and the Eagles are winning the kind of close games they lost in 2011.

Oh, but don't think for a moment that Eagles defenders can alter their assignments without bouncing the idea off their coach. "We're all part of it," Castillo said of the adjustment process. "Together."