WHAT THE EAGLES are plotting is the biggest playoff upset of the Andy Reid era. Make no mistake about that, about the size of the task, even if the New York Giants are only a four-point favorite on Sunday.

That the teams know each other so well is an advantage to neither of them. That they have played two wildly differing games this season, one a shootout and one much more buttoned-down, suggests nothing about No. 3. As Eagles quarterback Donovan McNabb said, "It's not going to be like the first two times," and he is right - because it almost never is.

If the Eagles are going to do this, if they are going to beat the Giants in their NFC Divisional Playoff game, it will not be because of Colonel Mustard with a candlestick in the conservatory. It will be because of Plaxico Burress with a Glock in the Latin Quarter. And that's it.

When Burress accidentally shot himself in the thigh in that nightclub, it gave the Eagles (and the thigh) their opening - and they all know it, everybody on both sides. When Burress allegedly shot himself with an unregistered weapon and then got himself jettisoned by the Giants, it gave the Eagles their chance. Some people say it isn't that simple, but it really is.

Jim Johnson, the Eagles' so-hot-right-now-he-is-incandescent defensive coordinator, would not agree with the simplicity, but he is too honest to dismiss the obvious.

"It makes a difference, there's no question about it," Johnson said. "We'll still mix up our coverages and fronts, but it makes a difference without Plaxico. The biggest thing with Plaxico was trying to get a good matchup. We didn't have anybody we

really could match up. We feel like we have a guy who can match up against [Domenik] Hixon a little bit, but Plaxico was so tall that it was hard to match up sometimes."

In theory, Burress should help the defense in two ways. First, it gives Johnson an extra safety to play with on many plays (given that he won't be needed to double-team Burress anymore). If you talk to some of the Eagles' players, it helped them especially against the run when the Eagles beat the Giants in December, just after the Burress thing blew up, so to speak.

And that's still the big issue here, especially with load-and-a-half running back Brandon Jacobs apparently feeling good about his oft-injured knee. As Johnson said, "Their running game is such a big part of what they want to do. They're No. 1 in the NFL in rushing. So, that's where you have to start."

The extra safety, the eighth man in the box, is a big part of making that work. In theory, it also should help them against the pass because that extra guy, in as many incarnations as Johnson dares to imagine, can be used to blitz Giants quarterback Eli Manning.

That would really seem to be an imperative this time because the Eagles' pass rush in the first two games has been pretty anemic. In their other 14 games, the Eagles averaged more than three sacks and nearly six hurries per game. Against the Giants, they averaged only a half-sack and 4 1/2 hurries.

They need to turn up the heat this time, somehow. They need to make Manning look around. Last year, as the Giants made their unexpected run to the Super Bowl, when he was forced to seek a bailout, Manning always seemed to find Burress - big man, easy to spot, seemingly born to make big plays.

This year, though, who will that guy be?

"I think we have more than just one game-breaking receiver," veteran wide receiver Amani Toomer said. "So I think that he was definitely a loss, but I think that there are a lot of guys in our room that can do some of the things that were done before."

Johnson seems to think it will be Hixon, but there really is no way to know if it will be as effective a combination.

"I think they like him a lot," Johnson said. "I think Eli likes him a lot. You can see him throwing the ball a lot to him. He is a talented receiver. He has good speed. The thing about Plaxico we all know is his great size and the speed he has. He's a unique player. I do know that they like Hixon and he is still a factor."

So those are some of the things that Johnson is plotting. You know that Reid and offensive coordinator Marty Mornhinweg are plotting, too, but they would seem to have more limited options. They are so banged up on their side of the ball - at running back and along the line - that it is hard to see them functioning as well they did earlier in the season. They seem to be aspiring to be efficient right now, not spectacular.

No, if the Eagles are going to do this, it is going to have to be about their defense, and about a gun that went off in the night. *

Send e-mail to hofmanr@phillynews.com, or read his blog, The Idle Rich, at http://go.philly.com/theidlerich.

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