After tonight there are no more predictions, no more projections and no more speculation. After tonight, the NFL season will have begun and it’s time to put the pre–season prognosticating to rest and let teams settle things on the field.

But for one last time before the games start counting for real, let’s examine what could potentially trip up contenders in both conferences. Below are 16 postseason contenders for the 2011 NFL season, along with 16 questions that revolve around concerns that that team has heading into the new year.

Patriots: What about the last line of defense?
The Patriots did a fantastic job this offseason addressing their need for more pass-rushers. But Bill Belichick may have created another weakness by leaving himself awfully thin at safety with the release of veterans Brandon Meriweather and James Sanders. Granted, Meriweather was less than impressive a year ago and Sanders has been injury prone throughout the years. For Meriweather, he often took bad angles to the ball last season and was caught out of position numerous times throughout the year. But in releasing both he and Sanders, Belichick is putting a lot of faith in Patrick Chung and 2010 rookie free agent Sergio Brown to man both safety positions. If Chung and Brown stay healthy and hold their own, then Belichick will once again look like a genius in his personnel decisions. If they falter, it doesn’t appear as though Belichick has left himself with a plan B.

Jets: Can Sanchez step up in the regular season?
If Mark Sanchez played as well in the regular season as he has in the postseason then maybe the Jets wouldn’t have to win playoff games on the road every year. Sanchez did take a step forward in his development last year but his consistency week-to-week remains an issue. This is a Jets team that could contend for a Super Bowl berth but not if Sanchez doesn’t continue to raise the level of his play. The goal for Rex Ryan and his team shouldn’t be the Super Bowl: it should be supplanting the Patriots in the AFC East first. Then they can set their sights a little higher.

Colts: How long will Peyton be out?
There’s no bigger question that needs to be answered for the Colts. With Manning they’ll once again be favored to win the AFC South. Without him they’ll probably sink to the bottom of the division. Kerry Collins may be able to keep this team afloat for a game or two, but without Manning the Colts will inevitably fall over a 16-game season. Hopefully for Indy’s sake Manning will return in a few weeks and more importantly, he’ll be close to 100-percent healthy. But there are reports that he’ll be out “a while” and if so, the next team on this list will have its shot to win the AFC South crown.

Texans: Is the defense really fixed?
Regular readers know that I fully believe this is the Texans’ year. I love the hiring of Wade Phillips, who has a long history of turning teams around in his first year as either head coach or defensive coordinator. This team also went a long way in shoring up a weakness with the signing of free agent cornerback Jonathan Joseph. But question still remain on that side of the ball. Is Mario Williams a linebacker? Can Kareem Jackson make strides in his second year? Will the safety position be a spot opponents can exploit? Arian Foster’s hamstring is a concern, as is whether or not Matt Schaub is the right man to get this team over the hump. But if the defense hasn’t been fixed then it won’t matter how much Foster or Schaub contribute because the Texans will fall short of expectations once again.

Steelers: Will the offensive line hold Pittsburgh back?
Once again the Steelers’ offensive line is a concern heading into the season. Granted, it was also a concern when they won the Super Bowl a couple of years ago and it was a concern last season when they lost to the Packers in the title game. Thanks to Dick LeBeau’s defense and the steady play of quarterback Ben Roethlisberger, this team always finds a way to overcome its shortcomings. That said, it’s often harder to stay on top of the mountain than it is to climb it and if there’s one spot opponents can exploit, it’s the Steelers’ O-line. (One could argue cornerback is another weakness of Pittsburgh’s, but it’s not a bigger concern than the O-line.)

Ravens: Can they beat the Steelers?
The only time the Ravens beat the Steelers last year was when Ben Roethlisberger was suspended early in the season. Otherwise, Baltimore played its AFC North rivals close but it can’t seem to get over the hump. Just like the Jets in the AFC East when it comes to the Patriots, before the Ravens can even think about reaching the Super Bowl they need to beat the Steelers first.

Chargers: Can they start fast for once?
This isn’t your brother’s Chiefs and Raiders that the Chargers now have to deal with. Kansas City is defending AFC West champions and basically returns the same team it won with last year, while Oakland is steadily improving. It used to be that the Bolts could sleepwalk through their first-half schedule before winning 10-straight games to cruise into the playoffs. But now a slow start could be detrimental to their postseason goals. The Chargers need to start fast for a change because the Chiefs and Raiders aren’t pushovers anymore.

Chiefs: Can they win against a tougher schedule?
The Chiefs proved last year that they’re a better team than people expected, but they also had a manageable schedule. This year, they face the Patriots, Steelers, Bears, Jets and Packers in five straight weeks during the second half of the season and won’t sneak up on anyone after winning the AFC West. It’s time to see if Matt Cassel and Co. can raise their game now that opponents will see them coming.

Cowboys: Will the offensive line and cornerback positions hold up?
Rookie offensive tackle Tryon Smith and cornerback Michael Jenkins both hurt their knees earlier this week and may not play in the Cowboys’ opener versus the Jets on Sunday night. Making things worse, Terence Newman has already been ruled out with a groin injury so an already worrisome spot for Dallas (secondary) just became an even bigger concern. I envision a bounce back year for the ‘Boys, but not if the offensive line can’t keep Tony Romo upright and not if the secondary can’t matchup up with the Eagles, Packers, Saints and Falcons (four of the best offenses in the conference) in the NFC.

Eagles: Can Vick live up to the expectations?
In 2004, there were low expectations for the Falcons because Michael Vick was coming off a devastating leg injury that cost him most of his 2003 season. So naturally Vick led Atlanta to the NFC title game that year. In 2005 when expectations were high, Vick was ONE OF the reasons the Falcons didn’t even make the playoffs. In 2006 when observers were predicting a bounce back year for Atlanta, again Vick and the Falcons fell short of expectations. Last year when Kevin Kolb was supposed to be the starter and Vick a gimmick in Andy Reid’s offense, Vick took the Eagles to new heights. Now, led by Vick, the Eagles are considered Super Bowl contenders. My point is that when expectations are high, Vick often falls well short. Is he an exceptional athlete? No f’n doubt. Can he win? Yes. Can he win a NFC title game with everything on the line? I’m not so sure and quite frankly, I lean more towards “no” after the way he’s been talking about how no defense can contain him. Vick can get awfully complacent when he wants to be.

Packers: Can the Pack repeat?
There’s really no other question, is there? Not since the 2004 and 2005 Patriots has a team won back-to-back Super Bowls in the NFL. And not since the 1993/94 Cowboys has a NFC team won back-to-back titles. Just like the Saints in 2009, the Packers have a great opportunity to end the NFC’s long drought but it’s incredibly difficult to repeat. For whatever reason, things are always just a little bit off in that next year and usually, injuries are a concern. (Although injuries were a concern for the Packers last year and they still won, so maybe this will be the year the NFC finally repeats again.)

Bears: Will the O-line and receivers be their Achilles’ heel?
The Bears’ offensive line was a disaster in its first preseason game this season, allowing nine sacks against the Bills. But it got better over the course of the next two weeks and seems less of a concern heading into the season than it did at the start of camp. That said, it’ll be interesting to see how guys like J’Marcus Webb and Gabe Carimi fare when teams start to game plan to stop the Bears’ offense. The same can be said for Chicago’s receiver corps, which was highly unimpressive in preseason. How the Bears believe Roy Williams is a starter is behind me, but Jerry Angelo will reap what he sows there. I have a hunch we could see a repeat of Jay Cutler’s 2009 season when his sack and interception totals were both high. And just like in ‘09, it won’t be all his fault like it’s portrayed in the media.

Falcons: Can Ryan win a playoff game?
The Falcons have a couple of question marks heading into the season, mostly on the defensive side of the ball. But they pale in comparison to whether or not Matt Ryan can take that next step, which includes winning a postseason game. He’s 0-2 in the playoffs, which hardly makes him Peyton Manning before the latter won a Super Bowl in Indy. But at the same time, Ryan needs to be the reserve of Mark Sanchez in that he needs to be just as good in the postseason as he is in the regular season. The Falcons are expected to unshackle him this season, which means putting him more in the no huddle (an offense he’s excelled in since his rookie year) and allowing him to throw more vertically down field (something that he’s struggled to find consistency with). With so many weapons around him in the offense, it’s time for Ryan to emerge as one of the elite.

Saints: Will the linebackers be a weakness once again?
The Saints did a fantastic job bolstering their defensive line this offseason with the signings of Aubrayo Franklin and Shaun Rogers, which should help Jonathan Vilma do a better job against the run than he did a year ago. Vilma was often taken out of the play because his defensive tackles didn’t protect him. That said, he also needs more help from his ‘backer mates. It’s puzzling why the Saints still feel that Scott Shanle is an every-down player when he’s proven otherwise for years. They’re also taking a huge risk assuming Will Herring can play every down when he was regulated to nickel duties in Seattle last season. This is a Super Bowl-caliber team but where the Saints can be had is at linebacker.

Rams: Can the Rams overcome a tough first-half schedule?
From my piece last week on the Rams: Have you checked out the Rams’ schedule this year? It’s freaking brutal. They open up at home against everyone’s chic pick the Eagles before heading to New York to play the Giants in Week 2. They come back to St. Louis for two home games and while one of those contests is a Week 4 matchup with the Redskins, the other is a Week 3 tilt against the Ravens. After they come back from their BYE in Week 5, the Rams travel to Green Bay and Dallas before hosting the Saints in Week 8. So in six of their first seven games they play the entire NFC East, the defending Super Bowl champions, and the team that won it all in 2009 and might be poised to do it again in 2011. Thanks, schedule makers!

Cardinals: Can Kevin Kolb play?
With how brutal the Rams’ schedule is, the Cardinals can win the NFC West if Kolb resembles even an average NFL quarterback. Obviously Arizona has other concerns, just like every team in the division. But the Kolb acquisition can put this team back on top in the West if he can show a smattering of consistency from week-to-week. That said, nobody knows whether or not this guy can even play. He looked good at times in Philadelphia but blew his chance to be a full-time starter last season. Time will tell if he’ll make the difference or not in the desert.