"It's Cowboys-Eagles time Sunday. That makes it discovery time.

For the third consecutive season, these clubs will play more than a game with two meetings in the final four weeks of the regular season. One club will measure itself against the other.

Two years ago, the Cowboys found themselves wanting after Philadelphia romped to a 44-6 win to keep Dallas out of the playoffs. That triggered an off-season of wholesale change by the Cowboys.

Last year, the Cowboys waxed the Eagles twice in one week – 24-0 in the final game of the regular season and 34-14 in a wild-card playoff game. Eagles president Joe Banner acknowledged there was "a gap" separating the NFC East champion Cowboys and Philadelphia.

"If you can't get motivated by that, I don't know what will motivate you," Eagles quarterback Michael Vick said in a conference call this week. "I wasn't even playing, and it hurt me deeply."

On Sunday night, the Cowboys will see for the first time this season how Philadelphia eliminated the gap by revamping its roster.

The Cowboys' post-Eagles changes took for one year. The Eagles threaten to stay in the front much longer.

"When you play a team as challenging as Philadelphia, the motivation is apparent," Cowboys interim head coach Jason Garrett said. "They've got a lot of good players."

And a lot of different players. This edition of the Eagles barely resembles the group the Cowboys chewed up last season. Philadelphia changed everything from the quarterback to the strength coach.

The Eagles return with eight new starters. Of the 45 players Philadelphia had in uniform for the playoff loss, 16 are no longer with the club.

The most conspicuous changes are at quarterback and running back.

Donovan McNabb , who threw for only one touchdown and took eight sacks in the losses to the Cowboys last season, is gone. Vick, a top MVP candidate, replaced him, after the club's brief flirtation with Kevin Kolb of Stephenville.

Brian Westbrook , who had only 48 yards from scrimmage in the losses to the Cowboys, is gone. LeSean McCoy, who ranks sixth in the league in yards from scrimmage with 113.1, has replaced him.

Eagles coach Andy Reid, in a conference call this week, insisted the losses to the Cowboys alone did not cause the changes.

"We were getting a little bit older as a team," Reid said. "That didn't necessarily have anything to do one way or the other with the games against the Cowboys. We were blessed with a bunch of draft picks. We needed to get a little bit younger, and we did that." "