The Panthers brought an end to a long-running NFL oddity last season when they became the first team to repeat as NFC South champions since the league realigned to eight divisions ahead of the 2002 season. Elsewhere, perennial front-runners in Denver and New England are at risk of falling back to the pack in their respective divisions, showcasing how the NFL is all but designed for turnover atop the standings. Which 2014 division champion is least likely to defend its title this season? SI.com's NFL staff makes its picks below.

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Chris Burke: Pittsburgh Steelers. Had a tough time with this question because I could see all eight of last season's division winners getting it done again. History has told us that probably won't happen.

I'm not envisioning a huge drop-off from 2014's 11–5 mark for the Steelers—the defense should be better and the offense features two of the top 10 offensive players in football (Le'Veon Bell and Antonio Brown). They have a couple of things going against them, though: Bell's looming suspension, which pre-appeal sits at three games, and a brutal schedule.

The Steelers do catch a break in their opener with Tom Brady likely joining Bell in suspension land, but they still open with four of their first six against '14 playoff teams. The homestretch is even worse. After a Week 11 bye, Pittsburgh wraps the season with home games against the Colts and and Broncos scattered within road trips to Seattle, Cincinnati, Baltimore and Cleveland.

In a division without much wiggle room thanks to the Bengals and Ravens' own Super Bowl hopes, the team that gets hot last might grab the crown. That's what happened a year ago as Pittsburgh closed with a 4–0 run, capped with a Week 17 win over Cincinnati. A repeat of that showing will be much harder to come by.

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​Doug Farrar: Denver Broncos. Those who believe in the Broncos' ability to take their fifth AFC West title in the last five seasons will tell you that Peyton Manning's downturn in performance toward the end of the 2014 season was more about injury than anything else, and that the legend hasn't lost it at age 39. They'll also tell you about the addition of defensive coordinator Wade Phillips, whose one-gap 3-4 schemes are a perfect fit for Denver's defensive personnel. And while that could all be true, there are concerns over the horizon. The Broncos replaced head coach John Fox with Gary Kubiak, whose offensive conservatism and focus on the running game may take away from what has made Denver great in the three seasons they've had Manning, and it's also possible that Manning's downturn in performance could be due to more than just a quadriceps injury. Add in the loss of tight end Julius Thomas in free agency and receiver Demaryius Thomas's dissatisfaction with his current contract, and the Broncos' offense could be working uphill no matter how good Manning is in 2015.

Moreover, the Chargers and Chiefs appear ready to challenge the Broncos for the divisional crown, and San Diego may have the inside track with the selection of running back Melvin Gordon out of Wisconsin in the first round of the draft. If first-round pick Melvin Gordon kicks the running game up a few notches, allowing Philip Rivers more open receivers and play-action opportunities, San Diego's offense may be the best in the West this year. Antonio Gates's four-game suspension to start the season is a hindrance, but the Chargers have also invested a lot in the rebuilding of their offensive line, and the defense looks to improve, as well.

Meanwhile, the Chiefs finally have a legitimate (if overpaid) No. 1 receiver in Jeremy Maclin, and first-round pick Marcus Peters has shutdown cornerback talent if he can keep his head on straight. The Broncos have done an estimable job of keeping their challengers at bay in this division, but this might be the year that all turns around.

Bette Marston: Dallas Cowboys. Despite low expectations coming into 2014, the Cowboys rode the record-breaking running of DeMarco Murray and the stellar play of Dez Bryant behind their young-but-impressive offensive line to a 12–4 finish and the NFC East title. Repeating won’t be as easy in '15.

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Dallas’s offense took a hit when Murray, who led the NFL with 1,845 rushing yards and 13 touchdowns last season, signed with the Eagles in free agency (Jerry Jones thinks that the team won’t miss him). While Bryant, who finished with 1,320 receiving yards and 16 touchdowns, will likely turn into the focal point of their offense, the Cowboys will certainly struggle to replace Murray’s production. Right now, the Cowboys plan to use Joseph Randle and veteran Darren McFadden, but the two running backs have never come anywhere near Murray’s 2014 level of production. Bryant will still be a headache for defensive backs around the league, but the Cowboys’ offense won’t be on the same level without last year’s power running game.

Across the division, Eagles coach Chip Kelly stole the off-season storylines with his show-stopping (and sometimes head-scratching) moves, signing Murray in free agency after trading away top back LeSean McCoy, letting top receiver Jeremy Maclin walk in free agency and swapping quarterbacks with the Rams. It’s clear that Kelly is gunning for the playoffs, and the Cowboys should be worried. Without their top running back and forced to lean on a wide receiver who hasn’t yet signed his franchise tag, Dallas’s perch atop the NFC East may be short-lived.

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​Amy Parlapiano: Carolina Panthers. The AFC West seems up for grabs, but even with Peyton Manning on the decline, I won't be convinced in July that a Manning-led team is less likely to repeat its division title than a team that won its division at 7–8–1. Carolina's crown last year was an indictment on the NFC South, not a sign that more titles are on the horizon. The Panthers, Saints and Falcons all fought to the bitter end to represent mediocrity in the playoffs last season, and it could have gone to any of the three (the Saints finished 7–9, the Falcons 6–10).

Hopefully 2015 isn't quite as miserable. Carolina should certainly contend, as it has the talent to win nine or 10 games, but I'm not ready to throw in the towel on the Saints yet. They shipped off Jimmy Graham but filled a major need in the process with center Max Unger, whose presence will be a huge boost to Drew Brees. And Dan Quinn has a chance now to completely re-tool the Falcons’ defense and balance out his team, which, with Matt Ryan and Julio Jones, has a very dangerous offense when it's clicking. Even the Bucs(!) are intriguing, as all eyes are on Jameis Winston. Sure, the Panthers may win the division again, but it'll be another toss-up—hopefully a more watchable toss-up than last year.

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Eric Single: Cowboys. The NFC South's long search for a repeat division champion may finally be over, but the NFC East has built up quite the drought of its own while we weren't paying attention. The 2004 Eagles are the last team to successfully defend the NFC East title.

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Philadelphia appears to be the biggest obstacle to the Cowboys' efforts to end that streak this year, but the Giants will also be a much tougher out in the second year of Ben McAdoo's offense if all of their weapons stay healthy. Is it possible that even the Cowboys' Week 17 date with the Redskins at AT&T Stadium will have something other than pride on the line? In spite of the franchise's recent run of dysfunction, Washington quietly improved this off-season under new general manager Scot McCloughan.

As expected, the Dallas off-season never lacked for drama, but the end product still has some disconcerting holes. I look at Rolando McClain's suspension, the unknowns surrounding the Greg Hardy signing and the DeMarco Murray-shaped void in the running game and see a fragile hold on NFC East supremacy.