Turnover is a fact of life in the NFL, where champs can become chumps before the leaves change.
Winning your division is great, but it isn't long before you're fending off three other well-stocked, hungry teams trying to knock you from your perch. Inevitably, someone eventually gets the better of you.
With the 2017 NFL Draft in the books and most major offseason roster moves behind us, let's examine the winner of each division in 2016 and identify those reigning title-holders who are most likely to be supplanted by an interloper in 2017. Below, I've ranked all eight defending division champs, from the least vulnerable to the most:
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8) Seattle Seahawks
The Seahawkstruly missedEarl Thomas after he broke his tibia in Week 13 last season. With the safety returning to health, this blue-chip-laden defense will be dominant. A slimmed-down Eddie Lacy can become the power rusher the Seahawks have missed since Marshawn Lynch departed. Signees Luke Joeckel and Oday Aboushi and second-round pick Ethan Pocic will give O-line coach Tom Cable the ability to mix and match and field a better unit in 2017. The Week 6 bye comes at a good time, and finishing with two of three games at home will help. Moreover, Russell Wilson, who has developed into a top-flight passer, will continue following in the footsteps of Drew Brees.
Biggest threat in the NFC West: With the 49ers and Rams breaking in new coaching regimes, the Cardinals look like the only viable threat at this point -- and QB Carson Palmer's age (37) makes them a question mark coming off a 7-8-1 campaign.
7) New England Patriots
Bill Belichick and Tom Brady are the most successful coach-QB combination in NFL history. They've won the AFC East 14 times in the last 16 seasons, and there's really no reason to think they won't take the title for a ninth straight year, especially with Belichick's slew of win-now acquisitions and the incredible organizational continuity. So why isn't New England No. 8? The schedule is brutal. After a Week 9 bye, the Patriots play five of six on the road. In Week 10, they visit Denver for a Sunday night game, then travel to Mexico City to face the Raiders. Then they play Miami in New England before three straight away contests: at Buffalo, at Miami and at Pittsburgh. That's a daunting stretch, and it opens the slightest crack of vulnerability.
6) Pittsburgh Steelers
Antonio Brown is 28 and has topped 100 catches in four consecutive years. Le'Veon Bell is 25 and just racked up 1,268 rushing yards and seven touchdowns in only 12 games. Ben Roethlisberger is 35, but he's coming off one of the better seasons of his career. Pittsburgh had a good draft: T.J. Watt can start, while James Conner, JuJu Smith-Schuster and long snapper Colin Holba can contribute. The defense played well in 2016, led by Stephon Tuitt and star linebacker Ryan Shazier. Who will replace Lawrence Timmons? Otherwise, the main question is, can the Big Three stay on the field together long enough to put this team over the hump?
Biggest threat in the AFC North: It's a toss-up between Cincinnati and Baltimore. Both have issues (the Bengals must deal with roster turnover, while the Ravens need to solidify the right tackle spot after losing Ricky Wagner), but both also have pretty good quarterbacks (Andy Dalton and Joe Flacco, respectively).
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5) Atlanta Falcons
Will the Falcons suffer from the typical Super Bowl hangover? Opening a new state-of-the-art stadium will help blunt some of that. How much will the No. 1 scoring offense from 2016 miss former coordinator Kyle Shanahan? Thanks to Matt Ryan's smarts, I'm confident the transition will be smooth. Ryan is coming off an unbelievable year, and receiver Julio Jones is as good as anyone in the league. The Devonta Freeman-Tevin Coleman running back combo is potent. The defense will be even better, thanks to the draft (Takkarist McKinley, Duke Riley), free agency (Dontari Poe) and the return to health of cornerback Desmond Trufant.
Biggest threat in the NFC South: This is a toss-up, with New Orleans, Carolina and Tampa Bay all improving, but I see the Buccaneers as the main challengers. Atlanta, meanwhile, needs to tidy up its pass protection after posting a minus-3 sack differential, in addition to addressing the aforementioned issues. Still, Dan Quinn is an excellent head coach, and I feel the supremely talented Falcons will come out on top.
4) Green Bay Packers
Aaron Rodgers remains the best quarterback in the NFL, and he exudes the type of confidence his teammates can feed off of in tough times. Last season -- in which the Packers overcame a 4-6 start to reach the NFC title game -- provided just the latest example. Coach Mike McCarthy does an excellent job making in-season adjustments, like moving receiver Ty Montgomery to running back. The secondary was a big reason that the Packers surrendered 153 points during a four-game losing streak (from Week 8 through Week 11) last season. This offseason, that group has been seriously upgraded, with the additions of second-round picks Kevin King and Josh Jones and veteran Davon House. Martellus Bennett is a terrific football player who should be a step up from Jared Cook, provided Bennett has the right attitude. Rookie running back Jamaal Williams is also pretty good.
Biggest threat in the NFC North: The Detroit Lions are the only team with a chance to unseat the Packers, though I ultimately don't think it will happen -- in fact, you could pretty much flip a coin between Green Bay and Atlanta in terms of actual vulnerability.
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3) Kansas City Chiefs
The Chiefs aren't dominant, but they are efficient, and they win because they're extremely well-coached on offense and defense. However, I didn't see them improve significantly from last season, with their premium draft capital being used on a player for the future (QB prospect Patrick Mahomes). (I did love the second-round selection of Tanoh Kpassagnon, who can be a really good pass rusher.) While Kansas City largely stood pat, the rest of the AFC West got better, making the Chiefs a prime candidate to fall.
Biggest threat in the AFC West: I think the Raiders -- with Derek Carr healthy, Marshawn Lynch carrying the ball and an improved defense -- will take the AFC West. The Chargers will be stronger, presuming many of the players lost to injuries in 2016 contribute. First-round pick Mike Williams will help a lot. And Denver still has a potent defense. All four teams are pretty evenly matched.
2) Dallas Cowboys
Dallas could finish anywhere from first to fourth in the NFC East, but I ultimately think the Cowboys will take step back. Dak Prescott and Ezekiel Elliott will need to duplicate their amazing performances as rookies last year -- that's a tall order. The schedule will be tougher, with seven games against playoff teams on the slate. Crucially, the juggernaut of an offensive line lost Doug Free and Ronald Leary, meaning some shuffling of pieces will be necessary. An eight-game stretch in which Dallas faces the Chiefs, Falcons, Raiders and Seahawks will determine whether the Cowboys can repeat.
Biggest threat in the NFC East: All three teams pose a challenge, but I think Washington will knock off the Cowboys in 2017. The Redskins really helped themselves on defense, both in free agency and the draft.
1) Houston Texans
Yes, Houston has a dominant defense, but I'm not sure how the Texans won nine games in 2016, given that they were outscored by 49 points with a turnover differential of minus-7 and a sack differential of minus-1. There are reasons for optimism. J.J. Watt will be back. The quarterback situation should be more palatable, whether first-round pick Deshaun Watson or holdover Tom Savage is the starter, after the turnover-laced tenure of Brock Osweiler. Bill O'Brien is a great coach. But while I like Watson's long-term potential, I still question whether the offense will be good enough, even with a world-beating defense, for Houston to keep up in the AFC South.
Biggest threat in the AFC South: The Titans, of course, also won nine games in 2016, and I think Tennessee has significantly improved, adding needed receiving talent in first-round pick Corey Davis and bolstering the defense. If he can stay healthy, Marcus Mariota will show us what he can do as a passer and a runner.
Follow Gil Brandt on Twitter @Gil_Brandt.