This is why preseason performances rarely matter. It's why predictions in August are a joke. And it's why five weeks into the NFL season, there isn't a single undefeated team left.

Despite all of the studied analysis and projected growth – all the knowledge you can wrap your brain around – you always get a team like the Green Bay Packers. A shoo-in for the playoffs, loaded with Pro Bowlers, and only one rush of momentum from the Super Bowl. At least, that's how it looks in August. But we are always reminded that September and October are the cruelest months. Two flips of the calendar and everything can change.

The Packers have to be feeling it right now: cursed, snake-bitten, or even earmarked for undoing. Have you lost count of the injuries? You have cornerback Al Harris(notes) (knee) and safety Atari Bigby(notes) (ankle) who won't come off the PUP (physically unable to perform) list until after Week 6. You have running back Ryan Grant(notes), who is done for the season, and linebacker Nick Barnett(notes) (wrist) and safety Morgan Burnett(notes) (knee) who will soon join him. Linebacker Brandon Chillar(notes) and tackle Mark Tauscher(notes) have shoulder issues. Just in that group alone, there are seven players who were either key starters or who had significant starting experience.

Sunday, against the Washington Redskins, it only got worse.

Quarterback Aaron Rodgers(notes) suffered a concussion. Tight end Jermichael Finley(notes) was carted off with a knee injury, and his backup, Donald Lee(notes), was knocked out with a bum shoulder. Linebacker Clay Matthews(notes) strained a troublesome hamstring. Rodgers, Finley and Matthews are playing at a Pro Bowl level, and Lee is arguably one of the best backup tight ends in the NFL. So, yes, a significant problem is developing here. And that's what makes the Packers this week's biggest loser.

Sunday's overtime loss to the Redskins hurt, but the implications of the injuries could be far more severe. Six weeks ago, it looked like this was going to be the team to beat in the NFC, even with the Saints returning almost all of last season's Super Bowl team intact. The difference for the Packers was that they were developing. They were poised to take the next step.

Packers tight end Jermichael Finley leaves the game on a cart after injuring his knee.
(Win McNamee/Getty Images)

How could you argue it? Rodgers had come into his own, and the offensive pieces around him had only gotten better with the development of guys like Finley and backup receivers Jordy Nelson(notes) and James Jones(notes). The offensive line was finally settled. The defense had some young pieces with another offseason of acclimation in Dom Capers' scheme.

Now? Who knows.

Rodgers will likely miss at least one game – basically the unwritten mandatory rule with concussed quarterbacks (see Jay Cutler(notes)). Finley needs further tests (never a good sign). And Matthews … Well, pulled hamstrings are some of the most maddening things a football player can deal with because they will linger unless they can be healed completely. Meanwhile, there's no telling how long it will take to get Harris and Bigby into playing shape after missing the first six games of the season.

And lest anyone forget, the 3-2 Packers are 2-2 in the conference and lagging a game behind the Bears in the NFC North. Of course, these facts might be irrelevant after Randy Moss(notes) acclimates to Brett Favre(notes) and the rest of the Minnesota Vikings. The point of all this, maybe the only thing that matters, is that Green Bay just spent five precious weeks failing to seize a strong hold on the division. And now that injuries are setting in, the rest of the division (OK, maybe not the Lions) seems ready to take advantage of the misfortune.

Six weeks ago, the Packers looked like an airtight division winner. Now the window is wide open, and the they don't look healthy enough to keep anyone from climbing through it.

Here are the rest of this week's losers and winners …

• 1972 Miami Dolphins
With the Chiefs' loss, there is no longer an undefeated team in the NFL. It's the first time since 1970 that the season has started without a 4-0 team. Pop the champagne.

Lions quarterback Shaun Hill scrambles against the Rams.
(Paul Sancya/AP Photo)

• Detroit Lions
Their 44-7 win over the Rams is the most lopsided since former general manager Matt Millen came to town and began a decade-long debacle. Perhaps most surprisingly, quarterback Shaun Hill(notes) has been stringing together solid performances. The Lions' defense was superb, but Hill's 227-yard, three-touchdown effort made all the difference.

• Chicago Bears coach Lovie Smith
Smith needed to get off to a good start to get the critics off his back, and the totally improbable 4-1 record after Sunday's win over the Panthers has done the job. The defense is playing well despite not having an elite pass rush, and the offense is making plays to win games. If Jay Cutler can come back healthy, the Bears have a schedule that could keep them in the playoff race into December.

• Baltimore Ravens
Their lone loss came by five points to Cincinnati, a game in which the Ravens played as poorly as ever this season and still could have won. I'm not sure they have been more impressive than they were against the Broncos. To give it some perspective, the Broncos just beat up a pretty good Titans team. Now they turn around and get absolutely manhandled by the Ravens, who are starting to crank up the running game. Again, I think this is the best team in the NFL right now.

• Tampa Bay Buccaneers quarterback Josh Freeman(notes)
The Bucs are 3-1. I keep blinking and looking at that record and can't believe it. Freeman is the reason why. The guy can make some unreal throws and keep drives alive in the clutch. His sideline pass to Micheal Spurlock setting up the game-winning field goal against the Bengals was so good it was absurd. Once again, I point to the Ben Roethlisberger(notes) comparison made by CBS analyst Gus Johnson. Freeman's team is nowhere near as talented as the ones Roethlisberger had early in his career, but it is a good comparison.

Falcons defensive end Kroy Biermann (71) heads for a 41-yard touchdown after intercepting a tipped ball.
(David Richard/AP Photo)

• Atlanta Falcons defensive end Kroy Biermann(notes)
Every once in a while, you see a moment that makes you realize even nondescript NFL players have amazing ability. Biermann provided one on Sunday, deflecting a Jake Delhomme(notes) pass like a volleyball, chasing it down and catching it, and then returning it for a game-sealing touchdown against the Browns. Check it out. Biermann isn't an athletic wonder, but that didn't stop him from making an astonishing play.

• Indianapolis Colts
They are scratching out wins, including Sunday's victory over an upstart Chiefs team. But every victory only seems to deepen concerns about the team's fatal flaws. The running game is just not happening. Too many injuries and no real push up front. And that is leading to a lot of zone coverages and cluttered passing lanes for quarterback Peyton Manning(notes). The upside is this is a very mentally strong team. But how long can it survive being one dimensional on offense?

• The Jacksonville Jaguars
I still think this team is a mirage, but at 3-2, you have to give it some respect. Jacksonville pulled itself together and beat a bad Bills team with some creative play-calling and a diverse attack. If the Jaguars run well, they win games. I still think Marcedes Lewis(notes) (2 touchdowns, 54 receiving yards vs. Bills) is one of the most underrated tight ends in the NFL.

• New York Giants wideout Hakeem Nicks(notes)
The guy looks like a faster Amani Toomer(notes). Sunday's 130-yard performance gives him 240 receiving yards in the last two games. He is clearly moving into place as Eli Manning's(notes) big-play read, with Steve Smith becoming more of a possession guy. Watch him use his body to wall off defenders. Finally, Manning has an unquestionable No. 1 again.

• Washington Redskins defense
Well, the losses have looked bad, and the wins have looked ugly. But the Redskins have still somehow managed to keep themselves atop the NFC East with the Giants and Eagles. The defense has quietly been the big reason for that, notably outside linebacker Brian Orakpo(notes). Watch some film on Orakpo, and you will see the best thing the previous regime ever did with a draft pick. As ugly as the offense has been at times, you know this is a team that will sink and swim with the defense.

Cardinals QB Max Hall celebrates beating the Saints.
(Mark J. Rebilas/US Presswire)

• Arizona Cardinals
I'm not sure I've ever seen an NFL game where a team scores 30 points without a rushing or passing touchdown. Perhaps more amazing, the Cardinals were doing it with rookie Max Hall(notes) under center. Oh, and it was against the defending Super Bowl champion Saints. The defense played extremely well, particularly against the running game. But I really think Hall made a huge difference, despite not being able to get the Cardinals into the end zone. He moved the ball well, kept the offensive competitive and let the defense do its thing.

• Tennessee Titans running back Chris Johnson
It has been a difficult season by Johnson's standards. His numbers are still fairly good, but his per-carry average (4.3) has been held down by the lack of his trademark home run plays. Those will come. They always do. And in the fourth quarter, it was Johnson's two touchdowns that won the game. Johnson's second half against the Cowboys may have been the best of his season.

• Oakland Raiders
Until the Chargers' final drive, it never felt like Oakland was losing control. And just when it looked like they were ready to slip, the Raiders came with back-to-back blitzes that changed everything. The defense gave up a lot, but it looked tough against the Chargers. It played with some grittiness. I'm not ready to call the Raiders an AFC West contender, but the door is opening.

• Carolina Panthers
Matt Moore was bad as a starting quarterback. Jimmy Clausen is worse right now. Carolina is going to have to go back to Moore to keep from hurting Clausen's development. This is a losing effort no matter who is in there, but there's no reason to throw Clausen to the wolves when he's clearly not prepared. Sprinkle him in later in the season, or at least establish the running game before going back to him.

Buccaneers defensive tackle Gerald McCoy (93) tries to tackle Bengals quarterback Carson Palmer.
(Mark Zerof/US Presswire)

• Cincinnati Bengals quarterback Carson Palmer
He's just far too inconsistent right now, and you can see the frustrations are starting to bubble up on offense. The key interception in the loss to Tampa wasn't Palmer's fault – the ball bounced off Chad Ochocinco's hands. But Palmer has been a faint shade of his former Pro Bowl self. His downfield accuracy isn't consistently there, and his pocket presence just doesn't look confident.

• Chiefs wideout Dwayne Bowe
The guy is headed back into coach Todd Haley's doghouse. You can bet on that after Bowe's stone hands made yet another costly appearance. His drop of a pivotal would-be touchdown pass likely cost the Chiefs their unblemished record. Perhaps the worst part about the situation is that it's not simply a matter of Bowe practicing harder. It's almost impossible to coach up bad hands. See Braylon Edwards.

• Denver Broncos defense
Getting stomped by Baltimore's running game is one thing, but there just don't seem to be a lot of finishers up front for the Broncos. I'm not sure there is a single player in the front seven who deserves double-team attention. This is where you start to miss Elvis Dumervil, because he created enough havoc and drew enough attention that it paid dividends for other players. Without him, this front seven is toothless.

• Houston Texans
The Texans have gotten slaughtered at home twice this season, and the back end of their defense might be among the worst in the NFL. First-round pick Kareem Jackson has been a significant liability. And I'm going to just go ahead and say it: Amobi Okoye may only be 23 years old, but he's a fourth-year veteran who isn't anything close to an impact player. Flashes don't count in your fourth year. It's time to produce.

• New Orleans running game
OK, the ground game is getting to be a concern. Pierre Thomas and Reggie Bush can't stay healthy, and Sunday showed what happens when you start to scrape the bottom of the depth chart. The Saints don't have a dependable running game right now, and it's putting Drew Brees in a situation where he has to force the issue to move the chains.

• San Diego Chargers coach Norv Turner
As usual, there are too many little things happening to not blame Turner. Blocked punts and penalties killed this team long before Philip Rivers lost the fumble that was returned for a game-clinching touchdown. We're talking about mental things and preparation things. And they keep happening over and over. As long as Turner is in place, this won't end.

• Dallas Cowboys coaching staff
This is really simple: When Tony Romo has more than 35 pass attempts, I blame the coaching staff. It's not a good thing for this team. That's not a knock on Romo. You can only run the game the way the coaching staff is dictating it. And when Romo throws more than 35 passes in a game, bad things happen for Dallas. Turnovers happen. It would be one thing if Romo were doing that with supreme protection, but he's not. So why is Romo throwing 46 passes against only 21 carries for the running backs?

(FIVE THINGS I LOVED AND FIVE THINGS I LOATHED)

Bears defensive end Julius Peppers salutes the crowd.
(Geoff Burke/Getty Images)

Loved: The deflection and interception on the same play by Chicago's Julius Peppers against Carolina. There may only be two or three defensive linemen in the NFL with the athleticism to pull off that play. It will endure as one of the best defensive plays of 2010.

Loathed: Seeing the leg of Rams wideout Mark Clayton fold up under him against Detroit. You have to feel for the hard-working Clayton, who became Sam Bradford's go-to guy and finally seemed to be realizing his talent this season. It's a huge loss for the Rams.

Loved: The fingertip touchdown catch and run by the Browns' Peyton Hillis in the second quarter against Atlanta. There is no more denying that he's a quality starting running back anymore. Find the third-quarter highlight of him trucking Falcons linebacker Curtis Lofton. Brutal.

Loathed: The embarrassing start by Houston's defense against the Giants. This is why people shy away from the Houston bandwagon. The Texans lure you in and then showcase their ability to collapse at the snap of a finger. Some of that has got to be coaching.

Loved: The way Detroit's Ndamukong Suh plays. He absolutely creamed Rams running back Kenneth Darby in the first quarter, blowing his own helmet off in the process. Suh's package of size, speed and power is just stunning. He's going to terrorize the NFC North for a long time.

Loathed: Hearing reports on Sunday that the Bills dealt Marshawn Lynch to Seattle without actively shopping him around the league. The management of this franchise is absurd, and it starts with the decisions at the top.

Loved: The special teams hit by Ravens linebacker on Broncos returner Demaryius Thomas. The impact caused a Thomas to fumble and then a ginger walk off the field. How is it that the Ravens always seem to be the hardest hitting team in the NFL?

Loathed: Seeing the pair of unsuccessful onside kicks by St. Louis and Kansas City. It's the second time this season the Chiefs have attempted and failed an onside kick. I'm not a fan of the play as a way to gain an edge early in a game. It's risky and gimmicky.

Loved: The 42-yard diving touchdown catch by Denver's Brandon Lloyd, who is playing like a top-end No. 1 wideout. Coaches and teammates have always talked about how good Lloyd could be if he'd just get his head screwed on straight. His fantastic start this year is another testament to that.

Loathed: Watching the Chiefs and wondering what in the world happened to Chris Chambers. He was brilliant down the stretch last season and signed a three-year, $15 million deal to be a dynamic No. 2 next to Dwayne Bowe. Five weeks in, only Minnesota's Bernard Berrian is keeping Chambers from being this year's most disappointing veteran wideout.