The winner of Sunday's game at RFK Stadium between the Washington Redskins and St. Louis Cardinals, the regular-season finale for both teams, will win the NFC East championship, according to the National Football League.

The Redskins (10-5) took sole possession of first place in the East with yesterday's victory over the Cowboys, who at 9-6 are tied for second place in the East with the New York Giants and Cardinals. Also involved in the wild card race are the Los Angeles Rams (10-5).

The Rams will play in San Francisco Friday night, the Giants will play the Saints in New Jersey Saturday and the Cowboys will play at Miami Monday night.

According to the NFL, there is one scenario in which the Redskins would miss the playoffs: if the Rams beat San Francisco and St. Louis beats Washington. That would give the Cardinals a 10-6 record and the NFC East championship (because they would sweep the Redskins in the regular season) and the Rams an 11-5 record and an automatic wild card spot.

Then, the Redskins and Giants both would be 10-6, assuming New York beats the Saints. Because the Redskins and Giants won their two games from Dallas, the Cowboys would be eliminated if all three were tied at 10-6. That would match the Giants and Redskins, and the Giants would win that tie by virtue of a better record in the NFC East, 5-3 to the Redskins' 4-4.

The Redskins did not play the Rams this season. In a tie breaker procedure, the first criterion between those teams would be their conference records. The Redskins, if they lose to St. Louis, would be 7-5 in the conference. If the Rams lose next week, they also would be 7-5.

That tie would then be broken by records against common opponents. The Redskins would win there with a 4-4 record against common rivals, compared to the Rams' 3-4 mark, the NFL said.

The Cowboys can make the playoffs only if they beat the Dolphins, and both the Cardinals and Rams lose. If that happens, the Cowboys would have a better record than St. Louis, 10-6 to 9-7, and would eliminate Los Angeles because they beat the Rams, 20-13, in the season opener.

Another way for the Giants to make the playoffs would be if Washington and the Rams both win and there is a three-way tie among the Giants, Cardinals and Cowboys at 9-7. The Giants would then win a wild-card berth by virtue of their head-to-head record against the Cardinals and Cowboys. The Giants would be 3-1, St. Louis 2-2 and Dallas 1-3.

The AFC Central race will go down to the wire between Pittsburgh (8-7) and Cincinnati (7-8). The Steelers would win the division if they beat the Raiders. But if Pittsburgh loses and the Bengals beat the Bills, Cincinnati would win the division based on a better record in the division, 5-1 to 3-3.

The AFC West will be decided in the last game between Seattle and Denver, both 12-3. The winner will win the division, the loser will get the wild card.

The Patriots were eliminated from the playoffs when they lost to the Eagles yesterday, and the Raiders will be the other AFC wild card team.

Miami's victory over the Colts yesterday assured the Dolphins the home-field advantage throughout the AFC playoffs, if they advance.