Not all division champions are created equal.
Some are able to string together a few years of dominance. Some fall within a year. Some -- well, really, *one* -- rule for more than a decade.
Let's take a look at the most vulnerable division winners from 2018 as we head toward the 2019 season. Below, you'll find all eight division winners ranked according to the likelihood that they will be replaced by a challenger, along with the team most likely to take their place. In other words, No. 8 is the safest reigning division winner and No. 1 is the most at risk. The rankings are presented in reverse order.
8) New England Patriots (AFC East)
There are challenges to overcome in New England; Rob Gronkowski has retired, while no one on the existing pass-catching corps -- which does include first-round pick N'Keal Harry -- topped 850 yards last season. Oh, and Tom Brady is 41. But the Patriots have won 10 straight AFC East titles. There is scant reason to believe they won't win their 11th. Bill Belichick is one of the best to ever coach in the NFL. Let's not overthink this.
Most likely to replace them: Buffalo Bills. Buffalo did a very good job of improving via the draft and free agency, and quarterback Josh Allen will play better in 2019 than he did in '18. But barring a huge leap by Allen, the Bills are not likely to displace New England. It would be foolhardy to bet against Belichick.
7) Dallas Cowboys (NFC East)
Amari Cooper made a real difference after arriving via trade last October. It will help Dak Prescott and the rest of the Cowboys' offense to have Cooper in the fold from the jump. It will also definitely be nice for them to welcome Pro Bowl center Travis Frederickback to work after he missed 2018 with Guillain-Barre syndrome. I like the promotion of Kellen Moore to offensive coordinator; I think Moore will be a head coach in the near future. And, of course, simply having Ezekiel Elliott -- the only person in the entire NFL to top 4,000 rushing yards over the three years he's been in the league -- gives Dallas a significant edge, provided no complications stem from his encounter with police at a music festival last weekend in Las Vegas. On defense, the retention of DeMarcus Lawrence and the additions of Robert Quinn, George Iloka and rookie Trysten Hill will boost a unit that ranked sixth in scoring and seventh overall in '18.
Most likely to replace them: Philadelphia Eagles. Unless the Giants or Redskins step up, this projects as a two-horse race between the Cowboys and Philadelphia, and while there is a good chance it will come down to the wire, I feel good about Dallas, which I see as the more stable team. Consider that Prescott has started every game of his three-year career, while Elliott has not missed time due to injury and Cooper was fully available in 2019. The Eagles are a legitimate threat, but QB Carson Wentz also missed the final portion of each of the last two seasons, and his current backup, Nate Sudfeld, has attempted just 25 NFL passes in his young life. I see the Cowboys emerging victorious.
6) New Orleans Saints (NFC South)
Getting so close to a Super Bowl appearance, only to have it yanked away under controversial circumstances, would take an emotional toll on any team. And that's even before you take into account the gut punch that ended New Orleans' 2017 playoff push. The Saints must leave the past behind. They must also hope the offensive struggles that marked the end of last season -- from Week 12 to Week 17, they topped 200 passing yards just once -- are not a sign that Drew Brees' days as a top-tier QB are coming to an end. I still have faith in the 40-year-old Brees -- who has been overcoming various doubts about his ability since his time at Purdue -- and in coach Sean Payton. We certainly have to give Brees the benefit of the doubt, based on his past track record. But as he comes off his first sub-4,000-yard season since 2005, his performance will be something to keep an eye on.
Most likely to replace them: Atlanta Falcons. I'm worried about Cam Newton's health in Carolina; shoulder surgery is especially concerning. If the Saints were to falter, I'd peg the Falcons and their Matt Ryan-led offense as the favorites to win the thing. For whatever it's worth, the Saints have never been division champs more than two years in a row.
5) Chicago Bears (NFC North)
The Robbie Gould curse continues to haunt this team. Chicago's search for a reliable kicker has continued into the offseason in the wake of Cody Parkey's infamous missed kick. Trade acquisitionEddy Pineiro would seem to be the current front-runner for the job, but he still must win it in the preseason. At defensive coordinator, the Bears are swapping Vic Fangio, who left to become the Broncos' head coach, for former Colts head coach Chuck Pagano, who has a proven track record as a quality defensive mind. Quarterback Mitch Trubisky is on track to take another step forward in Year 3. Don't forget that Trubisky only made 13 starts in college -- he'll keep growing as he continues to gather experience in the NFL, especially with the help of Matt Nagy.
Most likely to replace them: Minnesota Vikings. Though they appeared to fall asleep during a couple of games in 2018, the Vikings have a good quarterback (Kirk Cousins) and a stout defense. The improved offensive line will be key for Minnesota and Cousins. Like the Packers and Lions, the Vikings have reason to believe they'll perform better in 2019 -- but so do the Bears.
4) Kansas City Chiefs (AFC West)
There are reasons to be concerned about the Chiefs. Receiver Tyreek Hill is currently away from the team, with a child abuse investigation involving Hill having been reopened in April. Will speedy rookie Mecole Hardman be able to replace the two-time All-Pro? Aside from Hill, Kansas City can rest easy knowing Patrick Mahomes is an elite-level quarterback, while tight end Travis Kelce is coming off one of his best NFL seasons (103 catches, 1,336 yards and 10 scores) and running back Damien Williams stepped in ably after Kareem Huntwas released last November (Williams averaged 5.97 yards per carry in his three regular-season starts). New defensive coordinator Steve Spagnuolo is very good, and I think the acquisition of pass rusher Frank Clark will help a great deal. But how long will it take for the defensive overhaul, which includes a switch to the 4-3, to kick in?
Most likely to replace them: Los Angeles Chargers.Philip Rivers and Co. pushed Kansas City through Week 17 for the AFC West title last season, and they should be nipping at the Chiefs' heels again in '19. Denver and Oakland are also poised to take a step forward, but Rivers is very good, while he'll be working with top-notch receivers and running backs and an improved defense.
3) Los Angeles Rams (NFC West)
There is no time for the Rams to nurse a Super Bowl hangover, not with Seattle breathing down their necks and San Francisco welcoming a healthy Jimmy Garoppolo back to the fold in the NFC West. Key for Los Angeles: Will Jared Goff, a good quarterback who sometimes struggles with consistency, be able to regain his confidence and shake off a lousy performance in his team's Super Sunday loss? I'm also worried about running back Todd Gurley. He's a great player, but it is never good to see someone dealing with knee issues. Head coach Sean McVay is off the charts, a rising star in the NFL. But there are a lot of questions hanging in the air for the defending NFC champs.
Most likely to replace them: Seattle Seahawks. There's some question as to how much they'll miss the presence of traded-away pass rusher Frank Clark and receiver Doug Baldwin. But otherwise, I think Russell Wilson and Co. are in a good spot to make the Rams sweat.
2) Houston Texans (AFC South)
The Texans deserve credit for rebounding from an 0-3 start in 2018 to win the division -- but the flaws undergirding their embarrassing first-round playoff loss to the Colts are very real. For Houston to defend its crown, three things must happen. 1) The offensive line must perform better after allowing Deshaun Watson to be sacked a league-high 62 times in the regular season and three more times in the postseason defeat. 2) The overhaul in the secondary, with Tashaun Gipson, Bradley Roby, Briean Boddy-Calhoun and rookie Lonnie Johnson replacing Tyrann Mathieu, Kareem Jackson and Kevin Johnson, must pay dividends. 3) Watson and the passing game must take another step forward.
Most likely to replace them: Indianapolis Colts. Tennessee looks much improved from 2018, while there is nowhere for the Jaguars to go but up under new QB Nick Foles. But Indianapolis is a superior team when the resurgent Andrew Luck is firing on all cylinders. If he stays healthy again, the Colts have a chance to be pretty damn good.
1) Baltimore Ravens (AFC North)
The most pressing questions heading into 2018 -- Will John Harbaugh stick around as head coach? Will Lamar Jackson supplant Joe Flacco? -- were answeredaffirmatively. The quarterback drama might be settled, but there is even more uncertainty this offseason. Can Jackson take the next step as a passer under new offensive coordinator Greg Roman? On defense, Baltimore signed Earl Thomas to replace Eric Weddle. But the team also suffered significant losses in the front seven and pass-rushing corps, with Terrell Suggs, Za'Darius Smith and C.J. Mosley all heading for greener pastures -- and the Ravens are relying on younger players and free-agent stopgaps to fill the void.
Most likely to replace them: Pittsburgh Steelers. The Ravens' competition in the AFC North will be stout. The Browns are ascending, and Pittsburgh has been a perennial contender for almost all of the Ben Roethlisberger-Mike Tomlin era. The Steelers are facing something of a transition year, with running back Le'Veon Bell and receiver Antonio Brown both gone, but it would be silly to write them off at this point. To me, the race for "challenger" is a virtual toss-up between Pittsburgh and Cleveland, and to break the tie, I'll look to the team with more proven experience, including at quarterback.
Follow Gil Brandt on Twitter @Gil_Brandt.