By Sean Salisbury
Special to ESPN.com

The biggest reason why the Jets could unseat Denver this year is Bill Parcells. In every sport, there are difference-makers who are worth a handful of wins each year. In the NFL, Parcells is at the top of the list.

Parcells somehow wills his team to win. But it's neither will nor luck. Parcells is a preparation fanatic who knows every button to push. He knows which player to hassle, which player needs a kick in the rear-end and which player needs a pat on the back. It all starts there.

Last year, Vinny Testaverde showed how well he can play when he has confidence. I thought when Testaverde and Parcells got together, it would be a water and oil mix, but that wasn't the case. They are on the same page, and I expect Testaverde to play well again this season, putting up more big numbers.

The way Parcells has assembled the Jets has been huge. He has also gone out and acquired key players like Steve Atwater this season and Bryan Cox last year. He has a nice blend of youth and experience. The players will play their hearts out for Parcells. He's an old school coach; for a veteran who's loyal to him, Parcells will find a way to give him a couple more years if that player can help the football team.

There aren't many major negatives with the Jets, but this team is old at certain positions. And I'm concerned about the backup quarterback position. They waived Scott Zolak, and Ray Lucas isn't a proven backup. Parcells traded for Rick Mirer, whose confidence has plummeted since his rookie year. Maybe Parcells can have the same effect on Mirer that he had on Testaverde. I think that's what he's banking on.

It's so hard for a starting quarterback to finish 16 games that it is an aberration when it happens. If Testaverde only plays 13 games in the AFC East, the toughest division in football, two or three losses could be the difference between getting home-field advantage and winning the division or settling for the wild card.

Regardless, the Jets can run the football and play defense. They have a workhorse back in Curtis Martin, a ball-control receiver in Wayne Chrebet and a deep threat and control receiver in Keyshawn Johnson. They have a tight end, Eric Green, who can catch the football and dominate the line of scrimmage. The Jets also have a stingy defense and solid special teams.

Even if they don't look too spectacular, the Jets have what they need at every position. They do a little bit of everything well, and that should sustain them in the end for a run at Denver's title.

When you're trying to win a championship, all the parts have to be equally effective. With an outstanding defense and improving offense, the Dolphins have an excellent chance of unseating the Broncos this year.

The Dolphins might have been the best defensive team in the NFL last year. If they continue at that level and can be just as aggressive at the corner positions, with Terrell Buckley and Sam Madison challenging on every down, they will be difficult to attack through the air. Miami's front seven has a great mix of athleticism, size and power, making them just as tough against the run. On defense, the Dolphins have what it takes to win a championship.

Offensively, they have started to put the pieces together. The Dolphins have one of the best quarterbacks in the history of the game, Dan Marino, who will make great decisions and precise throws. Marino will do whatever is required in the passing game. He just needed receivers to step up.

The Dolphins have needed speed and experience at receiver, a void they filled with the acquisition of Tony Martin. The chemistry between Marino and Martin might be a little bit of a question mark at first, but it's showing signs of developing in the preseason.

The passing game might not be as big a concern as the running game because of the injuries they have had, especially Cecil Collins' ankle injury. Collins, who should be ready for the opener, adds power, strength and agility. The big rookie can get a yard on his own, which is what the Dolphins have lacked. Karim Abdul-Jabbar will be physical and play hard, but he's not as consistent as you'd like because he physically can't do it. Collins complements his physical ability with excellent speed.

Through the addition of guard Kevin Gogan, the Dolphins have tried to create an offensive line that's more aggressive in attacking the line of scrimmage and getting after defenses to create running lanes for their backs. Collins' versatility as a power and speed back adds a dimension that mixes well with an attacking offensive line.

An effective Collins will give the Dolphins the balance in their running attack that they need to win a Super Bowl. But he must be able to rebound from his ankle injury.