PHILADELPHIA -- That noted late-night philosopher David Letterman has frequently suggested there "is no off-switch" on the genius control.

Good thing for the Philadelphia Eagles, since resident genius and defensive coordinator Jim Johnson is being asked to work overtime again, trying to mesh five first-time starters into one of the most mentally challenging designs in the NFL. In fact, this marks a second straight season in which Johnson, who will never be confused, at least physically, with Jimmy Johnson (this guy's hair actually moves), has dealt with five new starters.

So how concerned is Johnson, who rebuffed San Francisco 49ers efforts to interview him for their head coach vacancy seven months ago, and instead signed a contract extension that makes him one of the league's best rewarded assistants? Well, until a reporter pointed out that he again had five new starters, Johnson hadn't even realized it.

"Yeah, I guess that's the case, huh?" said Johnson after a Wednesday afternoon practice. "But that's OK. We'll make it work. The (new) guys are doing fine."

Actually, there really are only two "new guys," middle linebacker Mark Simoneau and weak-side linebacker Nate Wayne, the other first-time starters having been with the club for at least a year. But even for the holdover players who have been elevated to starter's status for 2003, learning a defense with more permutations than just about any other in the league is a daunting challenge, one that makes daily play-book review a must.

It's a must, as well, that the five fresh starters meld quickly if the Eagles are to finally claim the Super Bowl title most of the team's veterans feel is their destiny. The season opener is a prime time matchup with the Tampa Bay Buccaneers, who obliterated the Eagles in the 2002 conference championship game. A New England team some feel is the class of the AFC East comes here in the second week of the season.

The Eagles then have their "bye" week, perilously early in the season, because it means they must then face 14 straight games with no time off. So whatever gestation period the new-look defense requires must be accelerated. The breaking-in period has to be taken care of in camp and the preseason.

With five changes in the starting lineup in 2002, Philadelphia finished statistically ranked No. 10 in overall defense, and advanced to a second consecutive NFC championship tilt. Another top 10 perch in overall defense might be acceptable this season. A third straight defeat in the conference championship game, though, simply won't be tolerated.

Even the two outsiders who have come here to start were made aware of that from the moment they stepped into the Eagles locker room. Not even the unique fresh-air recycling system unique to the Eagles locker room can filter out the disappointment of having twice advanced to within one victory of a Super Bowl appearance -- and failing.

"There's definitely a hunger around here," said Wayne, a five-year veteran signed as a free agent, after he was released by the Green Bay Packers for refusing to accept a salary reduction. "I've felt stuff like it before because, let's face it, the expectations in Green Bay are always high, too. But these guys, man, they are intense. It's like they will accept nothing less (than a Super Bowl appearance). No one talks about it but you know that it's there. So the pressure is on us new guys around here to help get it done."

Beyond the additions of Wayne and Simoneau, the three defensive players elevated to the starting lineup are: left end Derrick Burgess, a third-year veteran who had six sacks in his 2001 rookie campaign, but who missed all but one contest in '02 because of a broken foot; six-year veteran N.D. Kalu, who replaces the departed Hugh Douglas at right end, and who is coming off a season in which he posted a career-best eight sacks; and second-year strong safety Michael Lewis, a former second-round choice, and the successor to Blaine Bishop, who was released.

	Attack mode
	Over the past three seasons, the attack design of Philadelphia defensive coordinator Jim Johnson has produced impressive results. Here's where the unit ranks, since 2000, in a few key categories:
	Category	Rank
	Fewest points allowed	1
	Third-down efficiency	1
	Red-zone touchdown pct.	1
	Sacks	2
	Opponent passer rating	5
	Takeaways	7

Gone from the 2002 defense, besides Douglas, who signed with Jacksonville as a free agent, and Bishop, are middle linebacker Levon Kirkland and weak-side 'backer Shawn Barber. The former has essentially retired and the latter moved to Kansas City. Brandon Whiting, the starting left end in 2002, has been supplanted by Burgess and is now the No. 3 end.

The quintet of new guys averages just a dozen regular-season starts each. But take away Wayne's 40 starts with the Packers and the other four total only 19 starts. Of that group, Simoneau has the most starts, but only nine. Burgess and Kalu total six starts.

For a defense which over the past three seasons has ranked first in the league in fewest points allowed, is second in sacks and seventh in takeaways, that's a lot of inexperience to be trotting out onto the field. Then again, no one around here seems very concerned, and Johnson is confident enough that he has Simoneau calling the front seven adjustments while Lewis is responsible for the secondary calls.

"Kind of ironic, isn't it, that it worked out that way?" acknowledged Lewis, who started four games in '02, when Bishop was injured. "I mean, they've put a lot (of pressure) on me and Mark, but so far we've done OK. But by the time the season starts, you want to be perfect with every call, because bad things can happen when you're not."

Indeed, while the Johnson design incorporates lots of checks and balances, it's a system that toes a fine line between high reward and high risk. Few coordinators in the league still use as many zone-blitz packages as Johnson builds into his game plans, and while the blueprint is cleverly camouflaged and designed to cover up stress areas, there typically are some vulnerable spots when he starts bringing pass rushers from exotic angles.

The key, of course, is to get to the quarterback before he can get rid of the ball. And to do so, Johnson will harass opposition passers with rushes that come from the deep reaches of his seemingly endless bag of tricks. The old bromide that there is nothing new under the NFL sun might not apply to Johnson's pressure tactics. In the 2001 season opener he ran a blitz against St. Louis quarterback Kurt Warner, a double-cornerback fire, that clearly confused the Rams star and had him seeking out a friendly foxhole.

It may well be the most difficult defense, particularly from a pass protection standpoint, for which to prepare. And it is, Wayne allowed, a defense in which "you better have your head in the (play)book every night, or you're going to be lost out there."

But it is also a defense, once the players gain mental command of all details, in which it is fun to perform. Johnson loves to turn his players loose to the ball, espouses a pressure mode on every snap, and allowed on Wednesday that he often calls a blitz on the opening play just to get his charges into the attack mindset he demands.

The defense is lightning-fast, dizzying at times, places a premium on athleticism and on quickness, one reason the Eagles play with smaller performers on the flanks.

"What makes it conducive to what I do well, I think, is that it lets me run downhill to the ball," said Simoneau, obtained from the Atlanta Falcons in a springtime trade. "This is all about flying around, you know, making a decision and just going, you know. And I don't know many guys who don't like playing that way. It's pretty exciting to be turned loose like that. I mean, it's madness, but there's definitely a method to it. We're not just out there running around like a bunch of chickens with our heads cut off."

Then again, another season that concludes short of the Super Bowl, and the rowdy fans here might round up the entire Eagles organization and lead it to the guillotine. Just as Johnson craves pressure on the quarterback from the initial snap of the game, there is a lot of pressure on the Eagles and, as a result, on the five new defensive starters.

"We've got to perform," allowed Lewis. "No excuses. No doubt about it. Everyone here knows the expectations. The people in this (locker) room -- new, old, whatever -- know it far more than the people outside."

Len Pasquarelli is a senior writer for ESPN.com.