Well that's the multimillion-dollar question now, isn't it? The truth of that assertion will determine who stays and who goes in 2013, and that probably includes the head coach.
It most definitely includes the second-year defensive coordinator who, despite a first season that makes Sean McDermitt seem like Buddy Ryan in comparison, was given the keys again. OK, that's a slight exaggeration, but really no more so than a pile of statistics claiming Castillo coached a top 10 defense in the league last season.
As any fan who watched an NFL record five fourth-quarter leads dissipate last year can attest, numbers can be as misleading as the claims of a presidential candidate. They can perjure the future as well. Amid the hope generated by four late wins against four of the NFL's most waywards teams - Dolphins, Jets, Dallas, Washington - is the uneasy sense that it was fool's gold, that the sloppy tackling, missed assignments and general tentativeness that dominated that 4-8 start is the real personality of this team's defense.
Opponents converted nearly 50 percent of third downs of 5 yards or less (44 of 89) against the Eagles last season. They scored touchdowns in 17 of the 23 times they had a first down inside the 10. Only three times did they not come away with points. For all the talk of Michael Vick and the offense, the Eagles held the lead almost twice as long as their opponents did last season.
"Going through what we went through last year and not always being on the same page and still finishing in the top 10, we know we have the talent," Asomugha said. "We know we have the coaching - coach Bowles has helped out a lot too with the secondary. I think we're going to reach that."
But here's the thing: The Eagles have replaced several late-season regulars of that defense, including two linebackers and two members of the secondary. And while the intent of adding guys like DeMeco Ryans and drafting talented players like Mychal Kendricks and Brandon Boykin is to upgrade, they do not have the learning curve Asomugha referenced to fall back on. And while the latest preseason games have offered hope of cohesion and better tackling, there were moments . . .
Ryans, for example, has been solid but not spectacular. "When the season is over, I never remembered anybody going back and talking about the preseason," he said the other day. "You never hear anything else about it. It's just flavor of the month; that's what it was at the time. Football is back; this is what people have to talk about, but the season is what people remember."
Well, he might want to talk to Asomugha about that. The Eagles learned the hard way last year that the season is often an offshoot of preparation and persistence, two things severely lacking with this defense when the 2011 season began.
Will this one be different? Every team that falls short of a Super Bowl victory believes at this time of the season that it will.
Asomugha said the tale is in the tape.
"Like we played Pittsburgh in the preseason this year and we played them in the preseason last year. Watching the preseason last year was a little head scratching . . . Like, 'What's going on? Who are those guys?
"It's so bad it kind of pollutes your mind looking at it. You see so many guys just running around. You don't see that now. We're more comfortable and it shows."
"Our goal is to be the No. 1 defense in the league. Obviously, I think every team would say that, but I think it's attainable for us. It's not just a wish, like we're going to flip a coin - 'Hopefully, we'll be the best.' I think we can definitely be the best defense. But it takes a lot of focus."
Contact Sam Donnellon at firstname.lastname@example.org. Follow him on Twitter @samdonnellon. For recent columns, go to philly.com/SamDonnellon.