Donovan McNabb is not a running quarterback, but he is a moving quarterback, and therein lies the challenge for the Eagles' defense as it prepares to face a former teammate.
The Redskins frequently move McNabb with bootlegs and rollouts, buying him time behind an unsettled offensive line, confusing defenses and allowing him to fire passes from unexpected angles.
Both of McNabb's touchdown throws have come on plays on which he has faked handoffs, rolled out, and - using his remarkable arm strength - fired strikes back to the opposite side of the field.
Few quarterbacks have the power to make such long and accurate passes while moving away from their targets, but McNabb can, several Eagles defenders said.
"A lot of people say he doesn't run like he used [to], but I think he's more dangerous in the fact that he can get out of the pocket. He can create plays with his feet and throw the ball deep off one leg, across his body," said safety Quintin Mikell. "He can hit any throw, and I mean literally any throw, so as a DB, that's one of the toughest things to deal with."
Defenses typically focus on collapsing the pocket, but Washington's rollouts help McNabb avoid pressure and reposition while still eyeing his receivers.
With extra time, receivers can work deeper downfield, allowing McNabb to make the long throws he excels at. McNabb's arm is so powerful, defensive coordinator Sean McDermott said, that his options aren't limited even when he moves to one side.
The moves also help counter trouble in the Redskins' offensive line, which is dealing with an injury to starting left tackle Trent Williams, whose status for Sunday is uncertain, and a continuing competition at left guard. With McNabb on the move, the Redskins have allowed just five sacks in three games.
Limiting McNabb will come down to two keys: the defensive front controlling his movement, and the secondary sticking with the long pass routes.
"Keep him contained and get to him quick," said defensive end Trent Cole.
Defensive end Brandon Graham said the defensive backs would have to take away McNabb's first option, "so you can give the D-line time to get to him."
McNabb has been dangerous when moving.
Against the Texans in Week 2, he took a snap from the Houston 22-yard line, faked a handoff to the right, and rolled left. McNabb then stopped and rifled the ball back to the right, finding tight end Chris Cooley for a score. Cooley had started with a feint to the middle of the field - in the same direction as McNabb's bootleg - but cut back right, beating a linebacker.
Washington scored on a similar play last week. McNabb faked a handoff to the left and rolled right, getting outside a blitzing cornerback. McNabb moved outside the right hash, and, while still going right, launched an off-balance pass to the left. It traveled from the Rams' 28-yard-line to the back of the end zone, hitting an open Santana Moss.
"They're using Donovan in a way that he's very dangerous. They roll him out off the bootleg and get explosive receivers down the field and let him see the whole field, and not just half the field," McDermott said.
Cornerback Ellis Hobbs said defenders in pass coverage have to play honest, rather than trying to read routes and formations, because the receivers have more time to work and McNabb can throw to space rather than a specific route.
Some people have brought up the notion that the Eagles might have an advantage because they have seen McNabb up close for so long, but coaches and players said they have to be more focused on what he does in the Redskins' specific offense.
"You can't play a quarterback just on the way he throws the ball. You've got to play the scheme," said linebacker Stewart Bradley.
McNabb, of course, will also be familiar with many of the Eagles, but McDermott said the defensive calls change enough from year to year that he isn't worried about the quarterback picking up on Bradley's adjustments.
Some of those who practiced for years against McNabb but were barred from touching the franchise quarterback are looking forward to getting a shot at him.
"There's definitely going to be a lot of guys trying real hard to get back there, so it should be fun," defensive tackle Trevor Laws said.
Added Cole, "It's all free game, baby."