The Miami Dolphins (9-4) and New England Patriots (9-5) open the holiday weekend with a battle for first place in the final regular season game at Foxboro Stadium.
The Dolphins have won the last five meetings and can clinch their fifth straight playoff appearance with a victory. But the Patriots can move into sole possession of first in the AFC East and can also seal a playoff berth with a win Saturday along with losses by either the New York Jets, Baltimore or Seattle on Sunday.
"Everyone can talk about the playoffs, but the No. 1 goal you set on the first day of training camp is winning the AFC East," Patriots cornerback Ty Law said. "It's what December football is all about."
The Eagles (9-4) have a commanding three-game lead with three weeks left and can seal their first NFC East title since 1988 with a win on Saturday against the playoff-bound San Francisco 49ers (10-3).
Even if the Eagles lose, a loss by the New York Giants on Sunday will lock up the division for Philadelphia.
San Francisco clinched a wild card berth last week and trails the first-place St. Louis Rams by one game in the NFC West.
With Christmas Eve on Monday, the AFC West champion Oakland Raiders (10-3) host the Tennessee Titans (6-7) in the Saturday version of "Monday Night Football."
No one could have dreamed the Patriots would be in position to win the AFC East after two-time Pro Bowl quarterback Drew Bledsoe suffered a chest injury in Week Two. But under backup quarterback Tom Brady, the Patriots have gone 9-3.
Brady was only making his second start when the Patriots suffered a 30-10 loss at Miami on October 7. He completed just 12-of-24 passes for 86 yards and fumbled a snap that Dolphins defensive end Jason Taylor picked up and walked one yard into the end zone for a touchdown.
Miami dominated the line of scrimmage in that game, controlling the ball for over 36 minutes as Lamar Smith rushed for 144 yards and a touchdown. Brady also was sacked four times.
But New England is much improved since then and enters Saturday's contest with a four-game winning streak.
It will be the third game in 13 days for the Dolphins, who routed Indianapolis, 41-6 on Monday December 10 and then were blanked at San Francisco, 21-0 on Sunday, December 16.
If the Dolphins lose, they will be in danger of falling into third place since the Jets (8-5) swept them in the season series. The Jets visit Indianapolis on Sunday night.
The Eagles play at their best on the road, where they are 6-0, allowing a total of 38 points. And on Saturday, they will meet a Niners team that is listing quarterback Jeff Garcia as questionable with torn cartilage in his ribs.
With a playoff spot already clinched, the Niners may opt to sit out Garcia, who will likely take his share of hits from the blitz-happy Eagles, A master leader of San Francisco's West Coast offense, Garcia suffered the injury in the Niners' shutout of Miami last week. The Niners would have a significant dropoff if Garcia gets hurt with Rick Mirer as the backup.
If the Eagles lose this contest, things could get interesting as they close the season with a home game against the Giants and road contest against Tampa Bay.
Overall, the Eagles have won nine straight on the road, dating to last season. It is the longest streak since the Niners won 18 in a row from 1988-90.
Now that the AFC West title is out of the way, the Raiders continue to jockey for playoff position. They are one game ahead of Miami for a first-round bye and one game behind the Pittsburgh Steelers (11-2) for homefield advantage throughout the playoffs. The Steelers host Detroit (1-12) on Sunday.
Oakland secured its second straight division title with a 13-6 victory over the San Diego Chargers last Saturday.
The NFL's winningest team in the regular season over the previous two campaigns at 26-6, the Titans have slim playoff hopes, trailing Baltimore and the Jets by two games for the final two wild card berths.