It was a good performance and just in time. After stinking up the field last week against Pittsburgh, the defense needed a confidence builder. The Browns, unlike those spoilsport Steelers, appear to be just the team to provide that confidence, and any significance taken from the performance has to be tempered by the realization that Cleveland might be a horrendously bad team.
Nevertheless, Cleveland was the opponent, and the Eagles first-team defense pitched a shutout against the Browns first-team offense. It will be an easier news conference coming up for Castillo, who endured an interrogation along the lines of: "If you know what you're doing, [which is still open to debate], how are you going to do it with these guys?"
The Steelers made the Eagles look as they do when things are going badly - small, pliant, and unable to stop the run. The focus of criticism, as it usually does, fell on the linebackers. What good does it do to have the three best cornerbacks in the league if the guts of the team is marshmallow? Against the Steelers, that is how it looked, like a car with a lot of chrome but no engine.
Pittsburgh rang up a 21-0 lead in the first half, gaining 262 net yards, including 93 on the ground. The Steelers scored touchdowns on their first two drives, and it didn't get much better after that.
Well, it's amazing what another week of practice and the arrival of the Cleveland Browns can accomplish. On Thursday night, Castillo's guys looked a lot better. Instead of being small, they were fast. Instead of being soft, they were flexible. Instead of getting pushed around, they pushed back.
All of this could still be altered. The front office might cave in and acquire a veteran linebacker. The triple threat at cornerback might turn out to be a ruse all along, and one of the three will be dealt before the opener. Injuries could scramble the order of things.
So, take your significance where you find it, but there were some very good things that happened against the Browns. Some not so good, too - like the fact that safety Nate Allen still isn't strong enough to run with the starters - but mostly good.
If Thursday is a template, you can expect the Eagles to play specialty coverage an overwhelming percentage of the time. Castillo employed his three starting linebackers for most of the first few series to get them acquainted, but then it was specialty coverage 75-80 percent of the time.
Starting middle linebacker Casey Matthews has been something of a question mark entering the season because he is: (A) a rookie, (B) a fourth-round pick, and (C) he's playing a position he didn't play in college. All of that is fair enough, but he might not be on the field enough for it to matter.
In almost every situation except true short yardage, the Eagles went to at least nickel coverage, usually using Jamar Chaney and rookie Brian Rolle as the nickel linebackers while Dominique Rodgers-Cromartie joined the cornerbacks. In dime coverages, which they used far more often than usual, Chaney was the lone linebacker, and cornerback Brandon Hughes became the sixth defensive back.
For the most part, the coverages frustrated Cleveland quarterback Colt McCoy, and the Browns compiled just six first downs in the opening half (compared to 16 for Pittsburgh last week). Decent pressure from the defensive line helped, of course, but McCoy often had no options, even with time to throw.
Chaney had an excellent, aggressive game, as did safety Kurt Coleman. Chaney was able to make tackles as well as stay with his coverage assignments. His best play of the night might have been defending a pass thrown to 6-foot-3 tight end Benjamin Watson. Chaney climbed over Watson to knock down the ball but avoided a penalty by using his outside hand to reach past Watson's shoulder pads and get the pass. It was a textbook play.
The corners were as good as advertised, as least this time. Rodgers-Cromartie played in the slot on some occasions when he was on the field, and on others it was Nnamdi Asomugha who roamed the open areas like a free safety. Keeping up with who was where was confusing, and, of course, that's the idea.
Asante Samuel had an interception to short-circuit the one decent drive by the Browns, and it was pressure from the line and no better option that made it possible.
"I just hid a little bit, saw the ball in the air, and I do what I do . . . go get the ball," Samuel said. "We're looking pretty good. We still have a lot of work to do, [but] it was a good showing out here. We held the team in the first half to zero points. That's a pretty good showing."
Yes, and very different from the week before. What matters is what happens in another two weeks, naturally, but the defense needed this one.
Contact columnist Bob Ford at email@example.com. Read his blog, "Post Patterns," at www.philly.com/postpatterns