WASHINGTON — The Washington Redskins will know by the time they take the field Sunday night whether their postseason wild-card chances have been extinguished and their game against the Dallas Cowboys is a playoffs-or-bust showdown.

And coach Mike Shanahan says the team’s six-week run toward the playoffs has steeled it for the kind of pressure it will feel at FedEx Field, when it hosts the final game of the NFL regular season.

“I think it’s good. I think it’s really good. They get used to the pressure over the last six weeks, knowing every game is do or die,” Shanahan said. “They’re used to that scenario right now. They know we have to play our best football, and everything we’re working for comes back to this weekend: taking advantage of what we’ve done the last six weeks. It really doesn’t mean anything unless we take advantage of our game against Dallas.”

The NFL announced Sunday night that the game has been moved from 1 p.m. to 8:20 p.m. under the sport’s flexible scheduling arrangement with NBC. So while there is a chance the Redskins could reach the NFC playoffs as a wild-card team even with a loss to the Cowboys, it will have played out before the prime time game in Landover begins.

If the Redskins make the playoffs, it would be the first time since 2007 and the third time since 2005. A division title would be their first since 1999.

To earn a wild-card berth, the Redskins need both the Minnesota Vikings and Chicago Bears to lose Sunday. The Bears play at Detroit in a 1 p.m. game. The Vikings host the Green Bay Packers at 4:25 p.m.

If both teams are defeated, the Redskins would clinch a playoff berth before they play the Cowboys, and their night game would decide whether they go into the postseason as a division champion with a victory or as a wild card team with a defeat.

If either the Bears or Vikings win, the Redskins would be eliminated from wild card contention and their game against the Cowboys would be an all-or-nothing contest for the NFC East title.

“That’s what you work all summer for, all spring for, to be in those type of games in the winter, whether it comes in the last game of the season or the first game of the playoffs,” defensive tackle Barry Cofield said after the Redskins’ 27-20 win Sunday at Philadelphia.

If the Redskins win the division, they likely would play host to the Seattle Seahawks. If the Redskins reach the playoffs as a wild card, they likely would play at San Francisco as the NFC’s sixth seed.

The Redskins say they just have to keep winning. It’s all they’ve done since a Nov. 4 loss to the Carolina Panthers dropped their record to 3-6. They’ve won six straight games since then to improve to 9-6, and say they now expect to prevail in tight games.

“It’s the way you want to be. It’s the way good teams operate,” Cofield said. “You play to win. You expect to win. And losing is extremely disappointing. When you can have that kind of mind-set, have that kind of collective mind-set, the sky is the limit for your team. We gained that mind-set at the right time of the year. And we’re playing well enough to back it up.”

It is the second straight season in which the Cowboys will be playing for the NFC East title in the Sunday night regular season finale. They lost to the New York Giants, 31-14, in such a game last season and missed the playoffs.

The Giants went on to win the Super Bowl. The Redskins hope to follow in their footsteps.

“I’m glad we could keep this thing going,” cornerback Josh Wilson said after the victory in Philadelphia. “We’ve got to be undefeated for the rest of the year.”