Jeremy Maclin caught the ball and turned around with an airplane strip's worth of green in front of him, and the ground at Lincoln Financial Field seemed to tilt, as if he were suddenly running downhill. Maclin weaved to the middle of the field and back toward the sideline, his fellow wide receiver Jordan Matthews running interference for him throughout the 72-yard journey, until Maclin's right elbow landed on the Cowboys' 1-yard line. The Eagles scored a touchdown on the next play. After spotting the Cowboys a 21-point lead, they trailed by four. They took the lead less than three minutes later. It looked as if the ground might never tilt back.

It did.

The Eagles are in trouble, when it comes to the NFC playoffs. They lost to the Cowboys, 38-27, on Sunday night, and after at least sharing first place in the NFC East for most of this season, they are outside the conference's postseason window, pressed against the glass and peering in, hoping someone lets them back inside. They are 9-5, having lost back-to-back home games after winning their first six, and even if they win their final two games, against the awful Washington Redskins and the less-awful New York Giants, they will have to rely on the kindness of the Cowboys, and perhaps another NFC team or two, just to get in.

They lost Sunday because they couldn't cover Dez Bryant (who caught three touchdown passes) or Jason Witten (who caught seven passes) and because they committed three crushing fourth-quarter turnovers (two interceptions thrown by Mark Sanchez, a fumble by Brent Celek). But they lost mostly because they hit themselves with a haymaker on the opening kickoff and never quite recovered. Dan Bailey fluttered his kickoff well in front of Josh Huff, the Eagles' primary returner, and behind their last line of blockers, and all 11 Eagles on the field appeared to freeze. The ball hit the ground and bounced away from Huff, and the Cowboys recovered at the Eagles' 18-yard line and scored five plays later, and there was this bad feeling throughout the Linc, with good reason.

One three-and-out and another Cowboys touchdown followed - this one capping an 88-yard drive - and here was the nightmare scenario for the Eagles. Already their defense had been on the field too much and their offense too little. The week before, coach Chip Kelly had shown so little confidence in Sanchez that he installed a conservative, don't-lose-the-game-for-us-Mark game plan that never challenged the Seattle Seahawks' defense. Now down, 14-0, soon to be down, 21-0, the Eagles would need Sanchez to be something he is not if they were to win Sunday. He's not a quarterback who can put a team on his back. He never has been, and he wasn't against the Cowboys.

Even if he were, the truth is that the Eagles weren't ready to play Sunday, and that failure falls on Kelly. His offense produced no yards - forget first downs, no yards - in the first quarter. His defense (and yes, he is the head coach, so it is his defense) again couldn't get off the field on third down; the Cowboys converted on their first four third-down opportunities. It's been a persistent problem, and defensive coordinator Bill Davis hasn't been able to fix it. More, though, the Eagles didn't meet the measure of the moment Sunday. Its outcome has changed the course of the Eagles' season, and Kelly's strategy of treating every game the same backfired Sunday, because the Cowboys sure did a whole lot different.

"We have the same magnitude no matter what because it's always on the line," Kelly said last week. "I don't think one game is more significant than any other game. If you didn't prepare and win nine games to this point, this game would mean absolutely nothing. You just can't wake up one day and say, 'Hey this game is really important this week,' and then that diminishes the game the next week."

Kelly likes to engage in such semantic parries during his news conferences, but this time he was wrong. This was a big game. This one did mean more, and the Eagles took too long to show up and didn't stay all that long once they did. This was a far cry from Thanksgiving, when the Eagles routed the Cowboys, 33-10, in Arlington, Texas, and all things seemed possible for them. The season seemed to be tilting downhill for them then, too. It wasn't. And now it might never tilt back.