Ryan's return to Baltimore intriguing

Week 4 in the NFL proves you can go home again, and no return engagement is bigger than New York Jets coach Rex Ryan facing his old team in Baltimore on Sunday night.

Ryan was a member of the Ravens' organization from 1999 to 2008 as both defensive line coach and defensive coordinator, and many thought he should have been the replacement when Brian Billick was fired after the 2007 season. The Ravens struck gold when they instead hired John Harbaugh, who has taken the team to three straight playoff appearances.

Ryan proved his value with the Jets, though, taking them to two straight AFC title games. Ravens defensive players still love Ryan because he was a player's coach, but the Jets and the Ravens each will be trying to prove their toughness in what might be one of the most physical games of the season.

Ryan's return to Baltimore won't be the only interesting reunion. Former Chicago Bears defensive coordinator Ron Rivera returns to the Windy City as head coach of the Carolina Panthers, while former New England Patriots defensive lineman Richard Seymour will be trying to prove the Pats wrong for trading him.

Finally, two former Seattle Seahawks icons -- Cleveland Browns team president Mike Holmgren and Tennessee Titans QB Matt Hasselbeck -- get together in a Titans-Browns game in Cleveland.

Here are the top trends and matchups for Week 4:

1. Seeing more of Seymour: Figuring his contract was running out and he was getting older, New England sent Seymour to the Oakland Raiders prior to the 2009 season in return for a first-round draft choice. Now, Seymour gets a chance to prove he can dominate the team that gave up on him. Thanks to Seymour, the Raiders have a defensive line that can bully opponents. The Patriots, who used the Seymour pick to draft tackle Nate Solder this past April, have an offensive line that can be bullied. Tom Brady doesn't match up as well against defenses that play man coverage and can rush the middle of the field and get defenders around his legs. Seymour can do that and the Raiders play man. This will also be a bounce-back game for a Patriots defense that was destroyed last week by Ryan Fitzpatrick and the Buffalo Bills. At 2-1, the Pats don't want to fall into a black hole.

2. Vindication for Rivera; reunion for Holmgren and Hasselbeck: Bears coach Lovie Smith decided to go in a different direction on defense after the 2006 season and left Rivera scrambling for work. Rivera interviewed for numerous head-coaching positions, but his release pushed back his head-coaching clout five years. Now, Rivera returns to Soldier Field with a young Panthers team that may not be ready for prime time, but would love to help its new boss. Smith has struggled the past couple weeks. After a great opening win over the Falcons, the Bears and offensive coordinator Mike Martz can't get into any type of running offense. It has forced Jay Cutler to throw too many passes and forced Smith to order more running plays for Matt Forte going forward. In Cleveland, Hasselbeck and Holmgren can compare notes on why they are no longer in Seattle. Holmgren wanted to stay as the Seahawks' general manager, but the organization went a different way. Hasselbeck was offered a one-year, $7 million deal to stay in February, but once the lockout ended, the Seahawks opted to go with Tarvaris Jackson and now have one of the worst offenses in the league. The Seahawks' passing offense is one of the worst in football, while Hasselbeck is off to the best start of his career, averaging 311 yards per game with a passer rating over 100.

3. Dallas due for a letdown? The Cowboys had one of the most emotionally draining wins of the season Monday night when they came from behind to beat the Redskins 18-16. Quarterback Tony Romo, playing with a broken rib, had to endure the pain of the injury along with the frustration of having a young center who snapped the ball before he was ready and young receivers who didn't know where to line up. Felix Jones rushed for 115 yards despite a dislocated shoulder that was reinjured on the final drive. Wide receiver Miles Austin was out with a hamstring injury and Dez Bryant was less than 100 percent with a thigh injury. The Cowboys won on adrenaline. You wonder if they will come out flat like the Ravens did in Tennessee after an opening victory over the Steelers. The Cowboys host the red-hot Detroit Lions in a game before a bye week. Beware of the letdown.

4. Touring the AFC South: Concerned about a banged-up offensive line and an aging defense, the Pittsburgh Steelers will find out a lot about their team in a four-game tour of the AFC South, which started in Week 3 with a 23-20 victory over a Peyton Manning-less Colts team. Sunday's date with the Houston Texans will be a good measure of where the Steelers are. The Texans can do it all -- run the ball, pass it and play improved defense under Wade Phillips. Steelers corner Ike Taylor will be challenged by Andre Johnson. Steelers blockers will have to handle defensive end J.J. Watt and linebacker Mario Williams. A Matt Schaub-Ben Roethlisberger shootout will also be fun. The good news for the Steelers is that if they lose, they get the next two AFC South games -- Tennessee and Jacksonville -- at home.

5. The Beast and the Least: Week 4 features no divisional games -- a product of a league plan implemented in case the lockout shortened the season to 14 games -- and the NFC East has three games scheduled against the NFC West, the league's worst division. Each NFC East team already is 1-0 against the West, and the outcomes of the Giants-Cardinals, 49ers-Eagles and Redskins-Rams could send shockwaves to playoff contenders in the NFC South and NFC North. NFC East teams that go 4-0 or 3-1 against the NFC West would have the best chance of securing the No. 1 seed and wild-card spots. The NFC South went 13-3 against the NFC West last year and had three teams win at least 10 games. The struggling Falcons and Matt Ryan hope to turn around a 1-2 start beginning with a trip to 1-2 Seattle.

6. Fixing up some struggling parts: San Diego Chargers QB Philip Rivers is pressing. Rivers has thrown six interceptions in his first three games, and even though he has completed 68.3 percent of his passes, the offense isn't clicking. The Chargers can't afford a setback against the Dolphins this week. What worries them is a repeat of last season, when they struggled to keep Vincent Jackson, Antonio Gates and Malcom Floyd on the field together. Gates may miss another game with his bad foot. Floyd is slowed with a groin injury. Last year, the three were on the field together for only a single quarter and team missed the playoffs. As for the Packers, they will hope to tighten up a pass defense that's allowing 359.3 yards per game. That's right, 359.3. Pressuring the quarterback has been a problem, and this week Green Bay hosts Kyle Orton and the Denver Broncos.

7. Are they runners or trotters? The lockout robbed offensive lines of the time needed to jell, and everyone expected a slow start for the running games. After three weeks, rushing yardage per team is down to 103.9 yards per game, the slowest start since 2006 and off almost 5 yards from last year's average. There have been 17 100-yard rushing efforts compared with 49 100-yard receiving games in the first three weeks. Many top backs are off to slow starts. Chris Johnson of the Titans has 98 yards on 46 carries. Frank Gore of the 49ers has 148 yards on 59 carries. Rashard Mendenhall of the Steelers has a 3-yard per carry average. Shonn Green of the Jets is averaging 3.3. Steven Jackson of the Rams has been ailing with a quad injury. Arian Foster, Cadillac Williams, Knowshon Moreno and others have been hamstrung by hamstring injuries. Will that change in Week 4?

8. Who's worse off at 0-4? Five teams enter this weekend with 0-3 records, and the only near-certainty is either the Minnesota Vikings or Kansas City Chiefs should get their first win. They play each other in Arrowhead Stadium on Sunday, a Vikings team that can't finish against a Chiefs team that can't get started. Both teams have new offensive coordinators and quarterbacks (Donovan McNabb and Matt Cassel) who can't get into a rhythm. St. Louis Rams fans fear the worst with the Redskins visiting the Edward Jones Dome, because former Rams coach Jim Haslett brings in a blitzing 3-4 defense against a Rams team that can't block, can't get the ball downfield and has made Sam Bradford look like a rookie in his second year. The Colts head into Monday night's game against the Tampa Bay Buccaneers with a quarterback (Curtis Painter) who has a 33.3 completed percentage. They put two top defenders -- linebacker Gary Brackett and safety Melvin Bullitt -- on the injured reserve list. But of all the 0-3 teams, the Miami Dolphins and coach Tony Sparano face the toughest challenge. The Dolphins travel to San Diego. Owners who make coaching changes tend to look to bye weeks to make them happen, so Sparano and the Dolphins don't want to head into the bye week at 0-4, which is very likely.

9. Bungles in the Jungle: The Cincinnati Bengals didn't think anything of letting Ryan Fitzpatrick leave for Buffalo in free agency after Fitzpatrick backed up Carson Palmer in 2007 and 2008. Now, thanks to the play calling of Bills coach Chan Gailey, Fitzpatrick returns to Cincy as an early MVP candidate and one of the hottest quarterbacks in football. Go figure. Fitzpatrick may not believe what he sees when he gets there. Only 43,363 fans showed up for the home opener against the 49ers last Sunday. This week's game is blacked out locally. Bengals coach Marvin Lewis is fighting an uphill battle going with rookie quarterback Andy Dalton. Meanwhile, Palmer continues his so-called retirement, hoping for a trade that won't happen this season. The Bills could be 4-0 heading into next week's home game against the Philadelphia Eagles.

10. Go National? The AFC-NFC battle is tied at 4-4 after three weeks, but the NFC has a chance to jump into the lead. The Tampa Bay Buccaneers host a Colts team that may be headed to a four-win season. The Saints travel to Jacksonville, where Drew Brees should easily outduel Jags rookie Blaine Gabbert. Kyle Orton heads to Lambeau Field with an undermanned Broncos squad against a loaded Packers team. The fourth interconference game has the Chiefs hosting the Vikings.

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