Biggest Question Mark Facing Each Super Bowl Contender at NFL Training Camps

Even the best teams in the NFL will enter training camp with question marks ahead of the 2015 season. 

July and August are still the months of overflowing optimism, when every team believes it has a realistic chance at winning the Lombardi Trophy. But as is the reality most seasons, only a handful of teams are truly contenders to win the whole thing come February—and even those teams have uncertainties as camps open.

In the following slides, we will identify the biggest question mark tied to each early contender.

Contenders were selected by a number of factors, including roster talent and current Super Bowl odds. 

Just Missed the Cut

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Arizona Cardinals (Super Bowl odds: 25/1): Will Carson Palmer's knee hold up, and can the defense survive several key losses?

Baltimore Ravens (25/1): Can Joe Flacco handle another change of offensive coordinator?

Buffalo Bills (33/1): Who plays quarterback in Buffalo? And considering the options, does it even matter? 

Carolina Panthers (40/1): Is the offensive line—with Michael Oher now at left tackle—good enough for Cam Newton to take a step forward?

Cincinnati Bengals (33/1): Will a championship-quality roster finally get championship-quality quarterback play when it matters most?

Detroit Lions (40/1): Is the Ndamukong Suh-less defense suddenly a punchless one in Detroit?

Miami Dolphins (33/1): Can Ryan Tannehill continue his ascension with a changing supporting cast, and is the Miami defensive line capable of loosening Tom Brady's stranglehold on the AFC East?

Minnesota Vikings (33/1): How much will Adrian Peterson help Teddy Bridgewater's development in year two?

New York Giants (28/1): Eli Manning is ascending again in Ben McAdoo's offense, but can the Giants stop anyone on defense?

Philadelphia Eagles (20/1): How will all the new offensive pieces fit together? Is Sam Bradford finally healthy? Is the defense now good enough to get to the postseason?

Pittsburgh Steelers (22/1): The offense will be scary explosive, but is there enough talent and cohesion on defense for it all to come together?

San Diego Chargers (40/1): Will newcomers on the offensive line and first-round running back Melvin Gordon help ease Philip Rivers' burden?

Super Bowl odds via Odds Shark. 

New England Patriots

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Super Bowl Odds: 10/1

Question mark: How will the new secondary hold up?

The Patriots might lose Tom Brady for a number of games, but he'll eventually return. New England will survive his absence, regardless of whether it's four games or something shorter.

The more pressing issue is how the Patriots will handle their business in the secondary, where both Darrelle Revis and Brandon Browner are gone. New England is better in the front seven, and having Devin McCourty back at safety will help, but the talent level at cornerback is still a concern for the defending champions. 

Seattle Seahawks

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Super Bowl odds: 13/2

Question mark: When will the secondary be healthy?

Russell Wilson's contract negotiations are a major storyline, but it seems unlikely he'll let the back-and-forth distract him from playing his best football when the lights come on.

The bigger worry in Seattle is likely the health of the secondary, which remains the backbone of the club's defensive dominance. All-Pro cornerback Richard Sherman has rehabbed a serious elbow injury this offseason, while All-Pro safety Earl Thomas is still recovering from major shoulder surgery. 

"I'm unsure about everything at this point," Thomas told Ed Werder of ESPN this week. 

Green Bay Packers

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Super Bowl odds: 5/1

Question mark: Is the defense moving forward or backward?

The lasting memory of Green Bay's collapse in the NFC title game remains the trampling that the defense endured over the final few minutes and into overtime. Still, the unit otherwise dominated the first 58 minutes in a hostile environment, so there's reason for some level of optimism heading into 2015.

That said, the Packers are attempting to replace veteran cornerback Tramon Williams with a college safety (Damarious Randall) and a former college point guard (Quinten Rollins), and fourth-round pick Jake Ryan was the only addition at inside linebacker. Julius Peppers is now 35. Throw in early-season suspensions for defensive linemen Datone Jones and Letroy Guion, and the Packers defense is still the overriding question mark for the club entering camp. 

Dallas Cowboys

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Super Bowl odds: 12/1

Question mark: Will the defense rush the passer more effectively? 

Everyone wants to know who will take over lead back duties for DeMarco Murray, the reigning rushing champion who bolted for Philadelphia this offseason. It likely won't matter given all the talent Dallas possesses up front.

To truly take the next step, the Cowboys have to get better at rushing the passer. The offseason brought Greg Hardy and Randy Gregory, two obvious talents who could both be edge terrors if everything off the field falls into place. Both DeMarcus Lawrence and Tyrone Crawford look like young, ascending disruptors. Theoretically, Dallas could be difficult to handle up front if all the talent comes together. 

Denver Broncos

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Super Bowl odds: 12/1

Question mark: How will the Broncos' new-look offensive line protect Peyton Manning?

Much of the offseason hoopla has revolved around Manning's evolution within Gary Kubiak's new offense, but don't overlook Denver's changes along the offensive line.

Left tackle Ryan Clady tore his ACL and will be replaced by rookie Ty Sambrailo. Projected left guard Ben Garland is a former defensive tackle with zero career starts. Center Gino Gradkowski didn't start a game last season. Right guard Louis Vasquez and right tackle Chris Clark are the two lone holdovers.

The group is also attempting to learn Kubiak's complex blocking system. Manning will be fine in the new offense, but who knows about those tasked to protect him. 

Indianapolis Colts

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Super Bowl odds: 8/1

Question mark: Is the defense any better than the 2014 version? 

The Colts have surrounded Andrew Luck with new weapons, giving the offense an elite look. But what about the defense? 

Trent Cole, Kendall Langford and Dwight Lowery were strong veteran additions, and pass-rusher Robert Mathis will eventually return after missing the entire 2014 season. Still, there are lingering questions about Indy's ability to stop the run up front, and the group as a whole is lacking obvious difference-makers.

Can we consider the Colts defense good enough to win the AFC? Maybe camp will provide some early insight.