Carolina Panthers and the NFL's Most Dangerous Sleeper Teams

The National Football League is all about parity nowadays, and as the San Francisco 49ers demonstrated last season by going from 6-10 in 2010 to 13-3 in 2011, turnarounds can happen very quickly in today's NFL.

With that in mind, here's a look at some NFL teams who could be set for such a reversal in fortunes in 2012, beginning with a team that has just seen one of their own players throw down the proverbial gauntlet.

Carolina Panthers

That gauntlet was thrown down by Carolina Panthers center Ryan Kalil, who took out a full-page ad in Wednesday's Charlotte Observer in which the sixth-year veteran guaranteed a win for the Panthers in Super Bowl XLVII.

Whoa now. Settle down, big fella.

Kalil may have put the cart in front of the horse, so to speak, but there is reason for optimism in Charlotte.

The Panthers were a top-10 offensive team in 2011, led by quarterback Cam Newton's record-setting rookie season.

If newcomer Luke Kuechly and Carolina's 28th-ranked defense can improve their play this season, the Panthers could easily contend in an NFC South that is wide open in the wake of the "bountygate" sanctions levied against the New Orleans Saints.

Arizona Cardinals

The Arizona Cardinals got off to an absolutely atrocious start in 2011, and by the season's midway point, sat at 2-6 and were already out of the NFC West race.

However, that same Cardinals team flipped the script in the second half of the season.

Arizona went 6-2 down the stretch to finish the year at 8-8 and gave the team's fans reason to hope that this squad will return to contention in 2012.

This season, the Cardinals will go as far as their quarterback play will take them. Whether it's Kevin Kolb or John Skelton under center for the Redbirds this year, it's that play under center that will determine whether the Cardinals can give the San Francisco 49ers a run for their money.

Buffalo Bills

The Buffalo Bills haven't advanced to the postseason since 1999, and after finishing in last place in the AFC East for the fourth straight season in 2011, the team took a buzzsaw to its 26th-ranked defense.

The Bills are switching to a 4-3 defensive front in 2012 under new defensive coordinator Dave Wannstedt, and Buffalo took major steps to aid in that transition by adding defensive ends Mario Williams and Mark Anderson in free agency and selecting cornerback Stephon Gilmore in the first round of April's NFL draft.

On paper, the Bills now possess one of the more formidable defensive fronts in the National Football League. If Buffalo's re-tooled defense plays to its potential, then perhaps the Bills can finally put the curse of the "Music City Miracle" to rest this year.

Chicago Bears

It may seem a little strange to call the Bears a "sleeper" team in 2012. After all, through 10 games last year, the Bears were sitting at 7-3 and in the thick of the NFC playoff race.

However, injuries ravaged the Bears offense, the team dropped five games in a row and, just like that, Chicago's 2011 campaign was toast.

However, both quarterback Jay Cutler and running back Matt Forte are healthy again, and the team added their best receiving threat in years by acquiring wideout Brandon Marshall in an offseason trade with the Miami Dolphins.

With the ascension of the Detroit Lions, the NFC North has become a grueling division, but so long as injuries don't decimate the team again, the Bears should be able to hang in there with the Lions and Green Bay Packers this season.

Tennessee Titans

There was probably no more under-the-radar team in the National Football League with a winning record in 2011 than the Tennessee Titans.

The team quietly assembled a respectable 9-7 record despite a preseason holdout by star running back Chris Johnson and the loss of top wideout Kenny Britt for most of the year.

The Titans will likely have to do without Britt's services for at least part of this season as well. The fourth-year pro's latest brush with the law could earn him a league-mandated vacation to begin the season, according to Paul Kuharsky of ESPN.

The team will also need to answer the question of whether it will be veteran Matt Hasselbeck or youngster Jake Locker under center, but if Johnson returns to form in 2012 and the team's quarterback play is at least decent, the Titans should be a factor in a very winnable AFC South.