Eli Manning, Geno Smith facing a lot of pressure as 2014 season starts

The juxtaposition is stunning, and maybe a little bit frightening.

Over here is two-time Super Bowl MVP quarterback Eli Manning, whose preseason struggles in adapting to new offensive coordinator Ben McAdoo's West Coast offense have been the subject of continued -- and justifiable -- scrutiny and concern.

And over there is second-year quarterback Geno Smith, who has all of 16 NFL starts to his name but who looked completely comfortable -- we're talking well-worn-leather-jacket comfortable -- this summer in handling Marty Mornhinweg's time-tested system.

Yes, there's something very wrong with this picture. But how these two emerge from diametrically opposed training camp performances and transfer their talents over to the regular season probably will decide the fate of the Giants and Jets in 2014.

Will Manning's rookie-like struggles in the preseason, when he had one touchdown pass in five games, continue? Or will McAdoo's system finally resonate with a quarterback who spent most of the previous decade carrying out the commands of former coordinator Kevin Gilbride? The fate of Manning, McAdoo and coach Tom Coughlin could hang in the balance.

If Manning does address the issues that prompted team owner John Mara to call last year's offense "broken,'' the future looks bright for all three. Manning, 33, believes he still has a long way to go before his career is over, and a successful transition to the offense will ensure at least a handful of years to come. McAdoo will have earned the respect of his players. Coughlin, who shows no signs of slowing down at age 68, will be assured of coaching into 2015 and beyond.

But if this thing blows up, all three men might suffer. Manning's contract is up after 2015, and he's due to earn a whopping $17 million in salary in the final year of his deal. McAdoo's success is tied directly to Coughlin's; if the offense and the team underperform, McAdoo might be one-and-done, and a third straight season out of the playoffs could represent the end of Coughlin's tenure.

It may be hard to envision a coach who has won two Super Bowls and is a potential Hall of Fame candidate in danger of being forced out. But if this turns into another losing season, Mara almost certainly will consider making a change. Even if that's not something he wants to do.

Coughlin feels up to the challenge, but he knows this won't be easy.

"There are always challenges, there is always maneuverability,'' he said. "Very rarely is it set exactly to where you want it to be. What we have to do is get this group together as best as we possibly can and move forward.''

Rex Ryan has his own challenges, and his fate also might rest squarely in the hands of his quarterback. But while there is angst and legitimate concern about what lies ahead for the Giants, there is a sense of unbridled enthusiasm from the Jets and Smith.

Sure, there are continuing problems in the secondary because of a run of injuries at cornerback and the suspension and subsequent release of Dimitri Patterson. But Smith's apparent progress is the bigger story line, and if his improvement is legitimate, the Jets' playoff aspirations will be, too.

"I think Geno's done a great job,'' Ryan said. "He's very comfortable running the offense and I think he's ready to take a big step forward and continue some of the things he was doing late last season.''

You can get on Ryan for not staging a truly open competition between Smith and Michael Vick, but if the idea is to get your young quarterback to a higher level and be ready to lead this team well into the future, the plan succeeded.

That doesn't mean the production automatically will continue, but it is at least cause for optimism about Smith. He's a hard-working young quarterback who prepares as well as anyone could ask.

Two teams, two quarterbacks and two decidedly different dynamics surrounding both as they head into the season. The fate of the Giants and Jets rests in their hands.