The Super Bowl picture already has shifted. We've seen only three weeks of meaningful football, but that's already enough for ESPN's Football Power Index to produce a totally different set of Super Bowl odds. The reality we lived in -- the one where we thought the Patriots might go 16-0 and the Jets might go 0-16 -- is in the past.

For one, there's a new favorite atop the leaderboard. The Chiefs were ranked seventh in FPI's preseason Super Bowl odds, with a 4.3 percent chance of heading to Minnesota for Super Bowl LII and coming away with their first Lombardi trophy since 1969. Now, after beating the Patriots en route to a 3-0 start, FPI says the Chiefs have a 22.4 percent shot at winning their first championship since joining the NFL.

There were four teams who stood ahead of the pack before the season. Together, they had a 61.8 percent chance of winning the Super Bowl, according to FPI. They each had at least a 9.5 percent chance, with no other team topping 5 percent. Now? They've started a combined 7-5 and their Super Bowl odds have been cut nearly in half, falling to 32.6 percent.

Let's talk about those four teams and whether their fans should worry about their start to the season. I'm also going to get to the fifth-placed team, whose Super Bowl odds have improved dramatically but who might be flattered by their record. Let's begin, though, with the runaway favorites heading into the season:

Preseason Super Bowl odds: 32.4 percent

Current Super Bowl odds: 17.9 percent

The Patriots' Super Bowl odds are still second best in the league behind the Chiefs, but they've been cut nearly in half after a rough start to the season. It took a small miracle -- converting second-and-20 and third-and-18 against the Texans -- for the Patriots to avoid starting the season 1-2 with a pair of losses at home. Something is wrong in New England.

I won't keep you in suspense: It's the defense. The Patriots rank dead last in defensive DVOA through three weeks, and it's not particularly close. The Patriots have a 35.4 percent DVOA, while the 31st-ranked Saints are closer to the Falcons in 20th than they are to the Patriots in last. They rank last in points allowed, too (31.7 per game). It has been a brutal start.

Granted, some of the ugliness on defense involves the fact that the Pats started the season against a pair of impressive offenses in the Chiefs and Saints. DVOA considers quality of opposition, but those adjustments don't start kicking in until later in the season. The Patriots will look better once the algorithm realizes that the Chiefs and Saints are going to score on just about everyone they face.

Malcolm Butler has not had a strong start to the season, and he has played fewer snaps per game than he has the past two seasons. David Butler II/USA TODAY Sports

At the same time, though, that Texans game also counts. Houston's offense was basically useless against the Jaguars and Bengals through two weeks, scoring a combined 20 points, before dropping 27 points on the Patriots. (The Texans got to 33 with a Jadeveon Clowney defensive touchdown.) Deshaun Watson has been an exciting rookie quarterback, but the majority of the Houston offense in Week 2 came on one long scramble. Coach Bill Belichick and coordinator Matt Patricia weren't able to shut down an offense run by a guy making his second professional start. That's not normal.

If you had been trying to spot an obvious weakness for the Patriots heading into the season, it would have been their pass rush. It hasn't been good, but the Pats have gotten more out of the duo of Deatrich Wise and Trey Flowers than they would have hoped. Thanks to a monster game against a Saints team that was down both of its starting offensive tackles, Wise is tied for second in the league with nine quarterback knockdowns, trailing only DeMarcus Lawrence. Flowers and Wise have combined for five sacks and 14 hits through three games.

The problem is that there's not much behind those two. The rest of the defense has combined for one sack and three knockdowns, which isn't enough. Dont'a Hightower, who started the season as an edge defender after spending his career as an inside linebacker, got hurt during the Chiefs game and hasn't been back. On the whole, the Patriots have pressured opposing quarterbacks on just 22.8 percent of their dropbacks, which ranks 26th in the league. When they've gotten pressure, the Pats have done just fine: quarterbacks have produced a 43.4 passer rating against the Patriots when bothered, the ninth-lowest rate in the league.

When the Pats haven't gotten pressure, though, offenses have been setting them ablaze. The Patriots are allowing a league-worst 127.8 passer rating without pressure. For reference, Tom Brady's passer rating when unpressured last season was 125.6. Turning every quarterback you face into a Hall of Famer seems like a difficult way to win week after week.

The inability to hold up without pass pressure reveals the biggest problem with the Patriots so far: The secondary hasn't been very good. Outside of the skill positions on offense, it was supposed to be the best part of the 2017 Patriots. New England returned a pair of Pro Bowl caliber players in Malcolm Butler and Devin McCourty, alongside a veteran stalwart in Patrick Chung while making a rare foray into the top of the free-agent market to come away with Stephon Gilmore, who made his first Pro Bowl with the Bills last season.

None has lived up to expectations. Gilmore gave up big plays in each of his first two games and was hit for a 34-yard pass interference penalty against the Texans, although he did also grab his first interception with the team. The Saints led Chung around the field in Week 2. McCourty has been in coverage for two touchdowns in three weeks. Butler, meanwhile, was removed from the starting lineup after the opener and replaced by Eric Rowe before moving back into a regular role after Rowe got hurt.

The secondary should get better; Belichick's defenses have a habit of improving as the season goes along, and those players have a healthy track record of success. The Pats also are relatively deep in the secondary, where players such as Rowe, Jonathan Jones and Duron Harmon should keep Belichick from relying upon replacement-level talent in the case of injuries. It wouldn't be a surprise to see the Pats dip into the trade market to target a buy-low pass-rusher like Aaron Lynch from the 49ers, but the secondary won't be a season-long issue.

The offense has been just fine, ranking fifth in DVOA while facing two defenses likely to finish in the top 10 by the end of the season. Injuries to the receiving corps have left New England relying on Danny Amendola and Phillip Dorsett more than they might have liked so far this season, but I wouldn't be concerned about the receivers as long as the Patriots have their core three of Brandin Cooks, Chris Hogan and tight end Rob Gronkowski.

Tom Brady was sacked only 15 times in all of 2016, but he has been sacked 10 times through three games this season. Photo by Derick E. Hingle/USA TODAY Sports

More worrisome is what we've seen from the Patriots' tackles, who were supposed to be the cornerstone of the offensive line. Right tackle Marcus Cannon gave up a pair of critical sacks to star Chiefs edge rusher Justin Houston in the fourth quarter of Week 1, a figure that nearly matched Cannon's season-long total of 2.5 sacks allowed last season. He's out with a concussion and an ankle injury and has been limited in practice in advance of Week 4.

Left tackle Nate Solder, meanwhile, appears to be less than his usual self. Solder missed the entire preseason with an undisclosed injury and simply hasn't been very good so far. He has allowed three sacks in three games, including a pair of Brady takedowns against the Texans. Solder was mysteriously missing from warm-ups before the Texans game, but he also hasn't been listed on the injury report.

Again, though, the Patriots should be fine barring injury. The presence of Hall of Fame-caliber offensive line coach Dante Scarnecchia should be soothing for Patriots fans who are worried about protecting Brady. Swing tackle LaAdrian Waddle filled in admirably for Cannon last week, and while Cannon only really began to play like a great right tackle upon Scarnecchia's return from retirement last year, Solder has been a solid left tackle for years. The larger sample likely means more than the smaller one at this point.

The Patriots should be just fine. The biggest problem with their start has been that they're 1.5 games behind the Chiefs for home-field advantage in the AFC, and while they've got 13 games to make that up, the Pats would undoubtedly rather spend January at home as opposed to traveling West.

Preseason Super Bowl odds: 10.4 percent

Current Super Bowl odds: 4.8 percent

The Seahawks were FPI's preseason favorites to represent the NFC in the Super Bowl; now, they're fourth in their own conference. Seattle's biggest problem, of course, is the same as it has been for years: Its offensive line is truly atrocious. I can prove this to you with statistics, but sometimes, a picture is worth a thousand words:

The half-moon of regret that is the Seahawks offensive line. Couldn't protect for four seconds against a three-man rush on fourth-and-22. pic.twitter.com/kSVeZGLUjh — Bill Barnwell (@billbarnwell) September 24, 2017

It's one thing when the Seahawks were throwing out undrafted free agents and expecting them to contribute, but this is worse. General manager John Schneider has used high draft picks and spent money in free agency on linemen and this unit might actually be worse. Tom Cable described Luke Joeckel as one of the best left guards in football before suffering an injury last year after the Seahawks gave him a one-year, $8 million deal. Joeckel has been every bit as bad as he was in Jacksonville. Right tackle Germain Ifedi, the team's 2016 first-round pick, looks like he's playing the position for the first time a half-dozen times per game. The Seahawks already made a change at right guard in replacing Mark Glowinski with Oday Aboushi. Left tackle Rees Odhiambo hasn't been good in replacing George Fant, who was supposed to be the team's breakout lineman, but when your offensive line is irreparably broken because you lost a guy who was one of the league's worst left tackles last season, you didn't have a line to begin with.

There's little reason to think this group will get better. The trend of Seahawks offensive lines coalescing over the second half didn't take in 2016. Second-round pick Ethan Pocic has yet to play an offensive snap and could step into the lineup, but is there any reason to think that Cable will turn him into a worthwhile contributor?

Much of the offensive workload is subsequently falling on Russell Wilson to be a wizard. Coordinator Darrell Bevell has no faith in his running game, which is why Wilson has thrown 115 passes through three games. Wilson, who hadn't topped 500 passes in a single season before 2016, is on pace to throw 613 passes. Naturally, he's being pressured on 34.8 percent of his dropbacks so far, the fourth-highest rate in football.

What's far more surprising, though, is that the Seahawks are having trouble controlling the other side of the line of scrimmage. The Seattle front seven is struggling. The Seahawks rank 30th in DVOA against the run through three weeks. It's one thing to see the Titans light up someone with their running game, as they did in rushing for 195 yards on 35 carries (including a 75-yard run by DeMarco Murray) on the Seahawks last week. That's to be expected.

The Seahawks haven't been able to get their running game going, which has meant more throws for Russell Wilson. AP Photo/Mark Zaleski

The 49ers, though? San Francisco ran the ball 19 times for 159 yards against Seattle in Week 2, and while a chunk of that was a 61-yard run by Carlos Hyde, the 49ers averaged 5.4 yards per carry even if you take out the 61-yarder. (Also, it's bad to give up 60-plus yard runs in consecutive weeks!) The 49ers weren't anywhere near as efficient in their other games against the Panthers and Rams, so the Seahawks are the outlier here.

Even worse is that the Seahawks haven't had much of a pass rush since the first half of the season opener against the Packers. Even including that first half, Seattle is pressuring opposing quarterbacks on only 17.9 percent of its dropbacks through three weeks. That's the third-lowest rate in the league, ahead of only the Dolphins and Buccaneers. Cliff Avril & Co. have managed only a 5.4 percent sack rate, good for 24th in the league. Last season, their 29.8 percent pressure rate was the seventh best, while their 7.1 percent sack rate was the second best.

There's too much talent in the front seven for the defense to disappoint all season. The Colts should offer some respite this week, and after the perennial banana peel that is a Seahawks' road game against the Rams, coach Pete Carroll will have the bye to re-evaluate his defensive personnel. Fixing the offensive line, unfortunately, would require a time machine.

Preseason Super Bowl odds: 9.5 percent

Current Super Bowl odds: 4.1 percent

The Packers might have beaten the Seahawks and squeaked past the Bengals to make it to 2-1, but they've fallen even further in the Super Bowl hunt. Green Bay ranks as the team with the fifth-highest odds to make Super Bowl LII in the NFC. DVOA has the Packers as essentially an average team in 16th place, ranking between 11th and 19th in both offense, defense and special teams.

What DVOA and FPI both don't account for is injuries, and the Packers have been hit hard by them. While Aaron Rodgers is obviously Green Bay's best player, the Packers already have had seven key starters either miss a game or a significant portion of a game so far this year. That list includes two wide receivers (Jordy Nelson and Randall Cobb) and both starting tackles (David Bakhtiari and Bryan Bulaga). Three defensive starters have missed time in underrated superstar Mike Daniels, Davon House and Nick Perry, as has Ahmad Brooks, who would be Perry's backup.

The good news is that most of those injuries appear to be short-term ailments; everyone I mentioned is either back or expected to return shortly. Offensive line is the one notable concern, with backup linemen Don Barclay, Kyle Murphy and Jason Spriggs all on injured reserve. Bulaga made his return last week against Cincinnati but aggravated his ankle injury and is doubtful for Thursday night's game against the Bears, as is Bakhtiari.

What FPI does account for, though, is how difficult it might be for a team to make it through its division and win a title. While the Seahawks are 1-2, the NFC West doesn't exactly look dangerous. The Cardinals are wobbly. The 49ers are rebuilding. The Rams have been one of the league's most exciting teams, but they have a blowout win over the Colts and a narrow win over the 49ers. We'll know a lot more about Los Angeles after it plays the Cowboys and Seahawks in the next two weeks.

Aaron Rodgers has been sacked 13 times in three games, and he has an interception in each contest. Photo by Frank Mattia/Icon Sportswire

The NFC North looks a lot scarier. The Vikings are missing Sam Bradford, but they have two blowout wins over NFC South teams to their name, and their one loss is to a likely Super Bowl contender (Pittsburgh). The Lions came within a half-yard of starting 3-0, having faced three teams who expected to compete for a playoff spot in the NFC this season. Even the Bears are one drop in the end zone away from having beaten the Falcons and Steelers. This is a tough division.

FPI currently pegs the Vikings as favorites to win the North, with their 45.7 percent shot topping the Packers, who have fallen from 58.3 percent in the preseason to 34.4 percent after three weeks. I'd be skeptical of those numbers, if only because Bradford's status is so uncertain and because the Packers have been devastated by short-term injuries. If Bradford comes back soon and plays the way he did against the Saints in Week 1, or if players like Bakhtiari and Daniels start hitting injured reserve, the Packers will be in more serious trouble.

It's also likely that the Green Bay defense will improve, given that they've been disappointing in some unsustainably poor ways. For one, teams have thrown 82 passes without an interception against the Packers so far, which is remarkable for a defense that tied for fourth in the league with 17 interceptions last season. Even if the Packers don't come close to topping the charts again, they should at least force a few picks as the season goes along.

The Packers also have been terrible in the red zone; assuming seven points for a touchdown, Dom Capers' defense has allowed 5.9 points per red zone trip, the fourth-worst rate in football. They're too good to be that awful inside their 20. It's fair to note that the Packers also were terrible defending in the red zone last season, but last year's red zone performance has zero predictive value for what happens the following season. If the Packers have the league's 19th-best defense, chances are they'll have its 19th-best red zone defense, too.

Preseason Super Bowl odds: 9.5 percent

Current Super Bowl odds: 5.8 percent

Through three weeks, surprisingly, it has been the defense carrying the Steelers. Pittsburgh ranks 16th in points scored and third in points allowed. I suspect schedule strength has something to do with that -- Keith Butler's defense has faced DeShone Kizer, Case Keenum and Mike Glennon through three weeks -- but holding opposing offenses under 17 points per game should basically be a guaranteed victory given the talent of the Steelers' offense.

So far, though, the sum hasn't lived up to the individual parts. It's bizarre given that the band is finally all here. Martavis Bryant has been reinstated. Le'Veon Bell is both healthy and active. Ben Roethlisberger is 100 percent. Antonio Brown has been incredible, but he has been propping up the offense on his back so far. Brown has caught 26 of the 32 passes thrown his way and is averaging a league-leading 118 receiving yards per game.

Roethlisberger's stats had spiked with his triumvirate of weapons on the field, but he has been ordinary with the big three around this season. From 2014-2016, Roethlisberger took 193 dropbacks with Bell, Brown and Bryant on the field and averaged nearly 8.9 yards per attempt while posting a passer rating of 104.4. This season, though, he has dropped back 80 times with the Killer B's on the field and averaged just 6.2 yards per attempt while posting a passer rating of 93.2.

In part, the fireworks haven't launched because teams have been able to drop back into coverage and hold up. During that 2014-2016 stretch, teams blitzed the Bell-Brown-Bryant lineup a whopping 36.3 percent of the time and came away with pass pressure on only 20.2 percent of dropbacks. That's a losing ratio. So far in 2017, while the pressure rate against this lineup is down to 18.8 percent, teams are only sending extra rushers 21.3 percent of the time. Roethlisberger's sack rate is up from 5.2 percent to 6.3 percent.

There's more lurking underneath those numbers, though. Bryant should have caught a 75-yard touchdown pass on the opening snap of Sunday's loss to the Bears, but Roethlisberger led him too far and Bryant wasn't able to bring in the pass. Bryant and Brown are two of just eight receivers in the league to draw two or more pass interference penalties so far, and while they can't match the six drawn by DeAndre Hopkins, they've already racked up 122 yards in calls through three games.

Le'Veon Bell is averaging only 3.5 yards per carry on his 52 rushes this season. AP Photo/Nam Y. Huh

Bell has been the most disappointing player of the bunch, but I'm skeptical teams are going to keep holding him down. The league's highest-paid running back doesn't have a single rush or reception for longer than 15 yards, which seems unlikely for a back who had 17 such plays last season. Since his breakout season in 2014, Bell has turned 6.9 percent of his touches into plays of more than 15 yards, which means we already would expect him to have four or five big plays on his first 65 touches this season.

The best explanation for that, barring an unreported injury, isn't rust; it's randomness. The chances of Bell failing to record one 16-plus yard play at that rate are just under 1 percent, which is hardly crazy. The Steelers also have kept Bell's touches down early in the season, perhaps in an effort to keep him healthy for the playoffs. He's averaging 21.7 touches per game through three contests, down from an even 28 per game last season.

The Steelers also haven't been able to piece together long drives as a team. They're converting on just 32.4 percent of their third downs, tying them with the Jaguars and Giants for 26th in the league. The good news is that future success on third down is better predicted by the quality of a team's offense on first and second down than their previous success rate on third down, so if the Pittsburgh offense improves, its third-down success should come with it. The Steelers were above average in converting 41.1 percent of their third downs in 2016, and a similar rate wouldn't surprise me the rest of the way.

And while it has to worry Steelers fans to see Pittsburgh losing to the Bears a week after Chicago was blown off of the field by Tampa, the good news is that the loss didn't hurt their playoff chances. In fact, the Steelers were in much better shape after Week 3 despite their loss. After Week 2, FPI gave the 2-0 Steelers a 56.9 percent chance of winning the AFC North. With the Ravens, Bengals and Browns all joining the Steelers in losing last weekend, though, Pittsburgh's chances of claiming yet another division title actually soared to 72.9 percent.

Steelers fans have a lot to look forward to. The offense is going to improve. The defense might not be as impressive as it seems so far, but this is a deeper unit than we've seen in years. Keep in mind that regulars from years past such as James Harrison and Arthur Moats are playing fewer than five snaps per game; that depth could come in handy come January. The schedule also stays relatively friendly with the Ravens and Jaguars over the next two weeks. The first time we'll get to see the Steelers face a great offense is in a matchup that looms as massively important in the AFC seeding hunt: their playoff rematch against the Chiefs in Kansas City on Oct. 15.

Preseason Super Bowl odds: 4.9 percent

Current Super Bowl odds: 13.4 percent

I know: The Falcons are 3-0! Undefeated is good! If the Falcons have problems, they represent trouble 30 other NFL teams would happily sink into right now. Atlanta has banked those wins, and by virtue of claiming first place in the NFC at the moment, its Super Bowl odds have nearly tripled. In one way, the Falcons are off to as good of a start as any Atlanta fan could have hoped.

Look a little bit closer, though, and things aren't quite as rosy for the defending NFC champions. Two of their three wins have been remarkably tight. In Week 1, they beat the Bears but only after surviving a goal-line stand in which Chicago receivers dropped would-be game-winning passes on first and second down. Last Sunday, meanwhile, the Lions came within inches of pulling out a late-game victory of their own, with the Falcons having to survive three plays from the 1-yard line to stay undefeated. It's a wildly entertaining but totally unsustainable way to win road games.

Beating the Packers 34-23 in Week 2 was more impressive, but that was also a Packers team that was down its two best offensive linemen in David Bakhtiari and Bryan Bulaga before losing its two best non-Aaron Rodgers players, Mike Daniels and Jordy Nelson, after seven snaps each. Atlanta still deserved to win, and the score was only close after a pair of relatively meaningless fourth-quarter touchdowns, but the Falcons beat a watered-down version of the team they dominated in last season's NFC Championship Game.

The Falcons are averaging 29.0 points per game, down from 33.8 a year ago. Rey Del Rio/Getty Images

Advanced metrics suggest the Falcons have been a good but not great team through three weeks. Atlanta is ninth in the league in DVOA, which -- as I mentioned earlier -- isn't yet adjusted for quality of opposition. It ranks 11th by Pro-Football-Reference.com's simple rating system. Dan Quinn's team has a Pythagorean expected record of exactly 2-1. If you assume that the Falcons are going to win half of their close games, given that they've had two incredibly close games come to the wire, 2-1 makes total sense.

Good but not great also would describe the Falcons' offense, which was likely to drop back toward the pack after leading the league in offensive DVOA last season. Losing coordinator Kyle Shanahan was always going to hurt, but some of the elements of the Falcons' performance weren't sustainable on a year-over-year basis. Atlanta was the only team in the league to line up the same five-man offensive line for all 16 games last season, and that's already off the board this season. In addition to replacing retired guard Chris Chester, the Falcons have required a trip to the bench for right tackle Ryan Schraeder, who missed the Lions game with a concussion.

It also was going to be tough for the Falcons to be quite as good on first down as they were a year ago. The 2016 Falcons averaged 8.1 yards per play on first-and-10; ESPN Stats & Information has data going back through 2001, and no other team over that time frame averaged more than 7.4 yards per first-down play. Also, 30.6 percent of their first-and-10 plays resulted in a first down or a touchdown, which no other team came within 3 percentage points of hitting. The Falcons also had the league's lowest three-and-out rate.

This season, Atlanta has been just another good offense on first down. It is averaging 6.2 yards per play on first-and-10 and converting 24.0 percent of those plays for first downs or touchdowns, both of which rank 10th in the league through three games. The Falcons are actually converting a higher rate of their third downs so far, but without the historically impressive first-down offense, Steve Sarkisian's bunch is 12th in the league in three-and-outs.

While the Falcons' defense has improved a bit on the unit we saw during the 2016 regular season, it's not coming close to the sudden juggernaut that beat down the Seahawks and Packers and gave the Patriots fits before gassing out in the second half of the Super Bowl under the stress of a nearly unprecedented workload of snaps. After ranking 26th in DVOA during the regular season last season, the Falcons have made only a modest jump up to 20th this season.

What made the Atlanta defense jump off of the screen at times last January was a sudden flood of pass pressure. During the 2016 regular season, the Falcons pressured opposing quarterbacks 24.5 percent of the time, which sandwiched them between the Jets and Browns for 27th in the league. You don't want to be sandwiched between the Jets and Browns in any stat.

Vic Beasley Jr. had sacks in his first two games before injuring his hamstring. Kevin C. Cox/Getty Images

During the playoffs, though, the Falcons got after opposing quarterbacks and bothered them 39.9 percent of the time. For reference, the league's best pressure rate during the regular season belonged to the Broncos at 34.6 percent, and that was the best rate by more than 3 percentage points.

So far this season? The Falcons are right back where they were during the 2016 regular season. Atlanta ranks 20th, pressuring quarterbacks 25.9 percent of the time. Some of that owes to the absence of Vic Beasley Jr., who led the league in sacks last season (15.5) and went down during the Packers game with a hamstring injury. The Falcons have a 35.3 percent pressure rate over 34 dropbacks with Beasley on the field this season and a 23.0 percent rate over the 113 pass plays in which he has been on the bench. The difference might be the product of a small sample, though, given that the Falcons' pressure rate in 2016 was virtually identical with Beasley (24.4 percent) and without him (24.6 percent).

More disconcertingly, when the Falcons placed a defense-wide emphasis on targeting speed, they appear to have abandoned any hope of stopping the run. Atlanta ranked 28th in rush defense DVOA last season and has fallen even further to 31st this season. It's better to be awful against the run than it is against the pass in 2017, of course, but the Falcons were able to hide their run defense by virtue of blowing out so many teams in 2016. Atlanta has faced only 53 runs in 2017, the lowest per-game rate in football (17.6), but it is allowing 4.8 yards per rushing attempt. Only the Seahawks and Patriots have been worse.

Falcons fans should be delighted about their 3-0 record, and with the Bills and Dolphins coming to Atlanta on either side of a Week 5 bye, it would hardly be a surprise to see the Falcons hit 5-0 before they head to New England and begin a stretch of three straight road games on Oct. 22. At the same time, this also looks like a less impressive version of the 2016 Falcons team from the regular season, and while that's likely a playoff contender, Atlanta needs more out of its defense to compensate for the offense regressing toward the mean.