If there's one thing we've learned from the start of this NFL regular season, it's that experts don't know jack when it comes to making predictions.
Take a glance around the league, and you'll get the point. Some teams that dominated in 2007 are struggling to reach the right side of .500. Some that spent last postseason at home are leading their divisions. Yes, we see dramatic shifts in the NFL's power structure with each passing season. But it's rare to see so many teams in a given year that leave us asking so many questions.
It's so perplexing that it's worth examining some squads that have gotten off to good and bad starts. And we're not talking about rebuilding teams that are playing well (sorry, Atlanta and Miami), or good teams that have suffered tough losses (you should be thankful, Green Bay and Philadelphia). No, this column is all about two things: (1) which contenders really are pretenders, and (2) which disappointments are already primed to be written off.
Here are the teams:
1. Tennessee Titans (5-0)
How they got here: By doing what they've always done to be successful: playing tenacious defense and running the football. Defensive tackle Albert Haynesworth (five sacks) has been causing headaches for opposing blockers, and rookie Chris Johnson (381 yards) has become a rising star in just five weeks of regular-season play.
You also can't discount what quarterback Kerry Collins has meant in the wake of Vince Young's issues. This team easily could be a mess at this stage, which is a testament to coach Jeff Fisher's ability to manage a crisis.
Where they're heading: It's time to start accepting that the Titans are a pretty good team. They might not be the most entertaining bunch in the NFL, but they've won eight straight regular-season games dating to last season (which is tops in the league). As long as their defense continues to dominate -- they're first in the league in points allowed (11.2 per game) -- they're going to be in every contest. In other words, Fisher should do exactly what he promised, which is stick with Collins as long as this team is rolling.
2. Buffalo Bills (4-1)
How they got here: They have talented players in a variety of key positions on offense (quarterback Trent Edwards, running back Marshawn Lynch, wide receiver Lee Evans and left tackle Jason Peters), and their defense had been pretty reliable until it faced Arizona in a 41-17 loss in Week 5. For a team that was supposed to be one or two seasons from maturing into a playoff contender, the young Bills seem to be growing up fast.
Where they're heading: It's hard to really believe in the Bills until they become more consistent on offense. Their first setback was a concussion suffered by Edwards in Week 5 that could keep him out of Buffalo's next game -- Oct. 19 versus San Diego.
They also have benefited from a relatively weak schedule so far, one that has included wins over three teams (Seattle, Oakland and St. Louis) that have a combined record of 2-10. That said, the AFC East is wide open with Tom Brady gone for the season in New England. The Bills will be good enough to take that division title.
3. Washington Redskins (4-1)
How they got here: Great question. The Redskins were easily the least attractive team in the NFC East heading into this season, mainly because they had a first-year head coach (Jim Zorn) who was installing an entirely new offense. But it's amazing what can happen when you take care of the football. Quarterback Jason Campbell has yet to throw an interception in 153 pass attempts, and the Redskins have just one turnover in five games. There are probably plenty of reasons for their fast start, but that efficiency is the most obvious factor.
Where they're heading: It's easy to think the Redskins will fade eventually. The reality is they likely won't. Remember, they went into Philadelphia and beat a talented Eagles team in Week 5 after winning in Dallas a week earlier. If you can pull out tough wins in those places, you have to be considered a legitimate contender for the NFC East crown.
4. Chicago Bears (3-2)
How they got here: Give the Bears credit; their offense looks much better on the field than it ever did in paper. They've gotten solid play from quarterback Kyle Orton, and their defense ranks sixth in scoring (17.4 points per game). Even rookie running back Matt Forte (383 yards) has given the locals reason to believe general manager Jerry Angelo actually can draft offensive skill players who can play.
Where they're heading: This is one bandwagon that likely will fill up slowly. The Bears are improved, but they followed a big season-opening win at Indianapolis with two losses. They also have a habit of getting beaten up as the season progresses. In fact, they enjoyed a 34-7 win over Detroit in Week 5 without the services of defensive tackle Tommie Harris and cornerback Nathan Vasher (and it's only a matter of time before oft-injured safety Mike Brown suffers another season-ending injury). If the Bears stay healthy, they'll make a run at a playoff spot. It's just hard to believe that will happen.
1. San Diego Chargers (2-3)
How they got here: OK, they got upset in Miami and the defense has been inconsistent. But it's also fair to say that a last-second winning touchdown pass (by Carolina quarterback Jake Delhomme) and a lousy game-changing call (by referee Ed Hochuli in a loss to Denver) have led the Chargers to their current state.
As long as we're throwing out excuses, let's also add in that Shawne Merriman's season-ending knee injury and the banged-up physical states of three other stars (running back LaDainian Tomlinson, left tackle Marcus McNeill and tight end Antonio Gates) haven't helped matters.
Where they're heading: There's still reason to believe in the Chargers. For one thing, the AFC isn't exactly filled with heavyweights. The brilliant play of quarterback Philip Rivers -- who is enjoying the best season of his five-year career -- also has been uplifting for a team that could be in far worse shape. But here's the real kicker: The Chargers started 1-3 last season and wound up in the AFC Championship Game. As hard as it is to pull that feat off two years in a row, they'll be back in the postseason come January.
2. Jacksonville Jaguars (2-3)
How they got here: Injuries, injuries, injuries. The Jaguars have been playing with a patchwork offensive line since Week 1, and that has been the key reason for their demise. Their vaunted backfield combination of Maurice Jones-Drew and Fred Taylor has looked fairly ordinary, and quarterback David Garrard has been running for his life. This is a team that loves to control the tempo by beating up on opponents. At this point, the Jags just can't do that.
Where they're heading: Jacksonville plays in the one AFC division in which it's hard to rebound from a slow start. It currently has to contend with an undefeated Tennessee team and an Indianapolis squad that just avoided a 1-3 start with a comeback win over Houston. The Jags still have plenty of toughness. It's just that it's not going to be enough to get them back into the playoffs.
3. Seattle Seahawks (1-3)
How they got here: It's easy to point to an injury-ravaged receiving corps -- the Seahawks didn't have top wide receivers Deion Branch and Bobby Engram available until their 44-6 loss to the New York Giants in Week 5 -- but Seattle has glaring problems on defense. New York scored on its first six possessions in that contest, and Seattle is allowing 31 points a game. It's hard to win with those kinds of numbers.
Where they're heading: Let's face it: This is an aging team that has won the NFC West by default the past couple of years. The Seahawks have been the most consistent squad in a weak division, and they probably have been overrated as a result. It's still hard to think they won't be in the running for a division title come December -- especially as Arizona is still suspect -- but this looks like the year when they finally get exposed.
4. Minnesota Vikings (2-3)
How they got here: Too much faith in erratic quarterback Tarvaris Jackson and too much inconsistency in the secondary. The Vikings arguably have the best running game and one of the best rushing defenses in the NFL. But one-dimensional offenses and defenses can take a team only so far in this league. Minnesota once again is reminding us of that.
Where they're heading: It's difficult to write off the Vikings because they nearly made the playoffs with a strong finish in 2007. They're capable of doing that again, especially with Chicago and Green Bay (2-3) not exactly dominating the NFC North right now. A critical win over New Orleans was a good start, primarily because quarterback Gus Frerotte made some big plays in the passing game. Now, Minnesota has to capitalize on a schedule that gives it three NFC North games in the next four weeks.
Senior writer Jeffri Chadiha covers the NFL for ESPN.com.