What happens when an easily stoppable force meets an easily movable object? If Saturday's game between the Philadelphia Eagles and the Dallas Cowboys is close in the fourth quarter, we might find out.

Dallas and Philadelphia have been two of the worst fourth-quarter teams in the NFL this season. The Cowboys have led in the fourth quarter in five of their six losses, and in three of those games the fourth-quarter lead was at least 12 points. The Eagles have held fourth-quarter leads in five of their eight losses -- tough, close defeats at the hands of the Falcons, 49ers, Giants, Bears and Cardinals that have pushed their season into its current dire circumstances.

Their inability to hold fourth-quarter leads is the main reason one or both of these teams didn't lock up a playoff berth weeks ago. Each one is an extremely talented club that has shown ability to hang in games with some of the best teams in the NFL. But each is also adept, it would seem, at gakking away a game at the very end.

The Eagles made this a non-issue the first time these teams played, blowing the Cowboys out of the water in Week 8 in Philadelphia. And the way the Eagles have played the past two weeks, that could very well happen again. But if this game is close at the end, believe it or not, it's the Cowboys who are the better bet to pull it out. Although neither team can make a fourth-quarter stop, the Cowboys have at least shown the ability to score some fourth-quarter points.

With the help of the invaluable ESPN Stats & Information Group, we find that it's not just our imaginations. These teams are two of the worst fourth-quarter defensive teams in the league. The Eagles are allowing 100.6 yards per game in the fourth quarter this season, which ranks 26th in the league. The Cowboys rank 27th, allowing 101.9. Philadelphia has allowed 13 fourth-quarter touchdowns and Dallas has allowed 10. Both numbers rank near the bottom of the league. Opposing teams are averaging 75.1 passing yards per game in the fourth quarter against the Eagles, which ranks 24th in the league. The Cowboys are even worse, ranking 30th with 80.8 fourth-quarter passing yards allowed.

So yeah, I know, you're going to have a bunch of family over and the kids will be bouncing off the walls and looking out the window for Santa Claus, but the Stats & Info Group and I are here to tell you: Don't turn that television off in the fourth quarter.

The thing is, although both teams have been abysmal defensively in fourth quarters this season, the Cowboys have actually been a pretty good offensive team. Dallas is fourth in the league with an average of 109.6 yards of offense and third in the league with an average of 80.3 passing yards per fourth quarter. Their 11 fourth-quarter touchdowns are tied for eighth.

Tony Romo should be able to beat the Eagles' secondary with deep throws late if the Cowboys can keep the game close. In the first three quarters of games this season, the Eagles limit opponents to a 24.1 completion percentage, 8.8 yards per attempt and a league-low Total QBR of 46.1 on throws of 21 or more yards downfield. In the fourth quarter, those numbers go through the roof -- a 56.3 completion percentage, 20.1 yards per attempt and a Total QBR of 100.0, which is the highest possible Total QBR.

To recap: For three quarters, the Eagles' defense takes the big play away almost completely. But in the fourth quarter, it's all yours whenever you want it. As long as the Cowboys don't get destroyed the way they did early in the Week 8 game, they will have a chance to come back and win.

So will the Eagles, of course, but the difference is that Michael Vick & Co. aren't as good at actually doing it. The Eagles average 84.6 yards per game in the fourth quarter this season, which ranks 21st in the league. They average 52.4 passing yards per fourth quarter, which ranks 24th. And their seven fourth-quarter touchdowns represent the seventh-lowest such figure in the NFL. It is Vick's chief failure as a member of the Eagles that he has been unable to orchestrate a signature game-winning drive -- to bring the Eagles back from behind and win a game in the fourth quarter. The Eagles have done it once this season, and it was backup quarterback Vince Young who did it to the Giants.

Vick could get his chance Saturday. The way the Cowboys have been playing, there's every reason to expect this game to be close and high-scoring into and right on through the fourth quarter. But assuming it is, Romo's a better bet than Vick is to find a way to win it.