Division matchups loom large

After the conclusion of the World Series, the NFL heats up its most important matchups, so Week 10 begins the bonanza of divisional games.

Eight divisional games are featured Sunday and Monday, including a robust six in the NFC. Teams in the NFC East and NFC South are squaring off, and two of the top teams in the NFC West -- Seattle and Arizona -- battle in the desert. The Minnesota Vikings travel to the Chicago Bears for a key NFC North showdown.

But the best game of the weekend involves two top AFC teams: the Patriots and the Steelers. Here are the 10 best storylines and trends of the week:

1. A chess game between Bill Belichick and Dick LeBeau: The loss of Randy Moss may be starting to show in the New England Patriots' offense. Tom Brady's numbers have dropped the past three weeks. The always-accurate Brady has had 59.4, 59.3 and 52.8 completion percentages in that span. His yards per attempt have jumped up and down from 5.0 to 8.9 to 6.2. After averaging 21.3 completions a game with Moss, Brady has averaged 18 in his past three games. Also in the past three games, Brady has completed only 23 passes to wide receivers, as the offense evolves into one that throws more to the tight end.

It will be interesting to see whether Pittsburgh Steelers defensive coordinator Dick LeBeau copies some of the things Eric Mangini used to beat the Patriots last week. Mangini used an "Amoeba" scheme, in which all 11 defenders were standing and waiting to position themselves until the final seconds before the snap to confuse Brady. Mangini knows Brady will figure out the open pass-catcher if he gets a pre-snap read of who is in and out of the box. In passing situations, the Steelers do something similar and may have only one or two defensive linemen with their hands on the ground. What makes it tough for Brady is that he doesn't have a big-time running back to gash such schemes with running plays.

2. Getting the most out of a little: Kenny Britt, the Tennessee Titans' new home run-hitting receiver, popped a hamstring, and guess who becomes available to fill in against the Miami Dolphins? Randy Moss, the Babe Ruth of home run tosses. But this has to be a different feeling for Moss. Although he will like playing for a smart coach such as Jeff Fisher and a good group of Titans, he'll have to adjust to playing in a running offense for the first time in his career. He started his career in a Dennis Green-Brian Billick offense that became one of the most productive in NFL history. He had record-setting days with Tom Brady and the New England Patriots. In Tennessee, he comes to an offense that throws fewer passes than Brady completes in a game. Brady's usually good for about 23 completions a game. Vince Young is throwing only 17.4 attempts a game, completing 10.3. Britt caught 23 passes with an 18.9-yard average before hurting his hamstring, so Moss may get only three or four attempts thrown to him a game. The good news for Moss is that Young, according to ESPN Stats & Information, is the NFL's second-best quarterback on throws of 21 yards or longer. He has completed 9 of 22 for 324 yards, three touchdowns and a 127.8 quarterback rating.

3. Closing the book early on the Donovan McNabb trade: After 11 seasons that included eight trips to the playoffs, Philadelphia Eagles coach Andy Reid and the organization thought they could trade McNabb to the rival Washington Redskins and not miss a trip to the playoffs. Even though McNabb beat the Eagles 17-12 on Oct. 3, the Eagles are 5-3 and stand a good chance to make the postseason. A loss to McNabb could do serious damage to those playoff hopes, because it would put the Eagles at 0-2 in the division. Were the Eagles right in dealing McNabb to the Redskins? Washington coach Mike Shanahan has doubts about the trade, questioning McNabb's ability to pick up a new offense, run a two-minute offense and stay in condition while having a hamstring injury. Most now expect McNabb to walk after the season, because it's becoming apparent he's not getting a contract extension. If McNabb leaves, Eagles quarterback Michael Vick would be a logical replacement for him in Washington.

4. Last hurrah for Brett Favre and Brad Childress? The next two Sundays will define the Minnesota Vikings' season. They have an NFC North road trip to Chicago on Sunday and then host the Green Bay Packers. This past Sunday, Favre needed a career-best passing yards day to put together a come-from-behind overtime victory over the Cardinals. At 3-5, there is no margin of error for Minnesota, but if Favre and Childress can pull off back-to-back wins, they'd be 5-5 and within a game of first place. The Bears game is going to be hard enough. What's strange about this game is that it features Favre, Adrian Peterson, Jay Cutler and Mike Martz -- and both teams are averaging fewer than 20 points a game. Martz's brilliant play-calling has the Bears scoring 0.9 points fewer than last season under Ron Turner. Favre has returned to a Vikings team that is scoring 18.5 points per game, 9.9 less than last year.

5. Defining the bad race in the NFC West: By Sunday night, there might be some definition in the NFC West, considered one of the worst divisional races in years. The San Francisco 49ers visit the St. Louis Rams, and the Arizona Cardinals host the Seattle Seahawks. The Rams wouldn't necessarily eliminate the 49ers by beating them, because it's not out of the question that a 7-9 record could clinch this division. Still, a 49ers loss would put them three games behind with seven games left. Something has to give between the Cardinals and the Seahawks. The Cardinals have been their own worst enemies. Derek Anderson has seven interceptions and four fumbles. The bad news for Cardinals quarterbacks is that they've thrown nine touchdown passes -- six to Cardinals players and three to opponents via interceptions. The Cardinals are giving up seven points a game on interceptions or other returns. The Seahawks have been outscored 74-10 in the two games played since they beat the Cardinals by 12 points in Seattle on Oct. 24.

6. Not exactly headliners in the AFC: The only divisional games in the AFC are the Kansas City Chiefs at the Denver Broncos and the Houston Texans at the Jacksonville Jaguars. Broncos coach Josh McDaniels is trying to stop a one-year nosedive -- the Broncos were flying two miles high last season at 6-0 but have crash-landed with 12 losses in their last 16 games. The game is crucial to the Chiefs after their loss to the Oakland Raiders last week. The Chargers have three divisional home games in their next four games and could climb back in the AFC West race as long as the Chiefs stumble. For the Texans, the Jaguars game is a reality check. If they lose, they drop to 4-5 and last in the AFC South. The Texans have been giving up around 400 yards a game. If they give up 400 yards to a non-explosive Jaguars team, the Texans may be making calls to Wade Phillips to come fix the Texans' defense. The Jaguars have won four of the past six games in this series.

7. Does everyone love the backup quarterback? Eight backup quarterbacks are starting in the Week 10 weekend games. At least one backup will come up with a win, because the Detroit Lions-Buffalo Bills game features two backups: Shaun Hill of the Lions and Ryan Fitzpatrick of the Bills. Hill and Fitzpatrick have had interesting seasons. Although they've combined for 1-10 records, Hill is averaging 244.2 passing yards a game and 26.4 points a game in his starts, and Fitzpatrick is averaging 249.8 yards and 22.2 points a game.

Dolphins coach Tony Sparano made a bold move this week by benching Chad Henne for Chad Pennington. It's bold because the current Dolphins administration passed on Matt Ryan three years ago, hoping to get Henne in the second round. Pennington may provide a short-term spark to a Dolphins offense that doesn't finish drives, but if the move doesn't produce a playoff run, jobs might be on the line. The 49ers go with Troy Smith against the Rams. Rookie Colt McCoy of the Cleveland Browns faces the New York Jets, and rookie Jimmy Clausen goes for the Carolina Panthers against the Tampa Bay Buccaneers. Backups are 15-27 this season, completing only 57.7 percent of their passes for 180.5 yards and scoring 20.7 points a game.

8. Ghosts of the past: Browns coach Eric Mangini is going through the strangest two-week schedule of his head-coaching career. Last week, he outcoached and beat his pro mentor, Patriots coach Bill Belichick. On Sunday, Mangini faces a New York Jets team that fired him. The fascinating part of this meeting is how the Jets have moved their roster toward the top of the AFC through trades. Jets general manager Mike Tannenbaum picked up quarterback Mark Sanchez and wide receiver Braylon Edwards at the cost of a long list of former Jets role players. Mangini will try to beat the Jets with 11 former Jets -- Chansi Stuckey, Kenyon Coleman, David Bowens, Jason Trusnik, Eric Barton, Abram Elam, Blake Costanzo, Reggie Hodges, Brett Ratliff, Brian Schaefering and Ray Ventrone. Mangini's philosophy is winning with depth, loading up the middle and back of the roster. Tannenbaum and Jets coach Rex Ryan believe in stacking the front end of the roster. Rex gets a chance to go against his brother, Rob, the Browns' defensive coordinator. It will be interesting to see how four former Jets who are starting on defense handle Sanchez.

9. Not playing with a full deck: The Indianapolis Colts could have more injured players than the eight spots for deactivations, but Peyton Manning somehow manages to make the most out of anything he has. The Cincinnati Bengals are the opposite. The more talent they have, the worse they do. Marvin Lewis brought in Terrell Owens, Jordan Shipley and Jermaine Gresham, but their successes have come at the expense of their holdover stars -- Chad Ochocinco and running back Cedric Benson. Benson is still getting his 20 carries a game, but his yards per carry have dropped from 4.2 to 3.7. Ochocinco is still getting his five catches a game, but his 11.8 yard-per-catch average is the second lowest of his career. Carson Palmer is on pace for a 4,200-yard season after barely getting more than 3,000 last year, but the end result is that the Bengals are 2-6.

10. Bottom-feeders: Could this be the Bills' one chance to get a win? Probably. They are catching the Lions a week after they lost Matthew Stafford to a third-degree shoulder separation. The Bills have lost three three-point heartbreakers in a row. If the Bills win, the Panthers might end up on track to get the top pick in the draft. John Fox goes back to Jimmy Clausen after losing Matt Moore for the season, but he hasn't let Clausen be Clausen. The Panthers average only 21 plays a game out of three-receiver sets, according to ESPN Stats & Information, one of the lowest totals in the league.

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.