As the era of free agency and the salary cap approached in the early 1990s, general managers contemplated the dilemma that would arise. They envisioned locker rooms divided, separated by the haves and the have-nots. How, they wondered, would teammates coexist in a world in which five or six players may dominate 30 to 40 percent of the payroll?

The results became clear. Chemistry is essential for a team to succeed. Look at the visual images of recent Super Bowl successes. The Broncos won back-to-back Super Bowls with the symbol of a hard-working back, Terrell Davis, who gave his teammates salutes after touchdowns. High- and low-paid Rams offensive stars formed a circle in the end zone doing the Bob-&-Weave, chanting "Got to go to work." Ravens linebacker Ray Lewis gathered his teammates before kickoffs and had them growl and chant like hungry dogs.

	As long as Terrell Owens catches 93 passes a season, he won't be a chemistry problem.

And the Patriots, an overachieving team put in the right spots to succeed by coach Bill Belichick, symbolized the ultimate success story for great team chemistry. Belichick brought in new players near the minimum in salaries and produced the maximum in efficiency.

Good chemistry wins. Bad chemistry tears a team apart. But the story goes beyond just the headlines that break out during the tough times. The 49ers grew as a winning franchise even though their best player, wide receiver Terrell Owens, verbally sparred with coach Steve Mariucci. Not everyone has to get along and not everyone will on a football team. Keyshawn Johnson and Warren Sapp may not be great buddies, but they can coexist as long as the teams win.

"You've got so many guys on a team, and a lot of them aren't going to get along," Dolphins middle linebacker Zach Thomas said. "But when you are on the field, I don't care if you don't like somebody, you are going to go all out of course. You've got to do your job. The thing in a locker room is if a guy is missing practice and everyone knows that he's not wanting to come on the field and play, it's like a cancer and it affects your play. It spreads quickly."

Perhaps the biggest decision Belichick made on the way to winning the Super Bowl was suspending wide receiver Terry Glenn. No one questions Glenn's skills. Packers coach Mike Sherman, in fact, traded for Glenn with the idea of making him Brett Favre's "go-to" receiver in a Super Bowl run.

Glenn, however, let his off-the-field problems and spats with management affect his play last season. He was absent too many times when the team needed him. Though the Patriots couldn't afford to lose his ability to make the big offensive play, they survived and thrived without him.

"More than just the chemistry of getting along and not fighting amongst yourselves is accountability," Dolphins defensive end Jason Taylor said. "The key for a team is everyone being accountable. Is this guy working as hard as I am? My biggest fear is three or four years from now, you look back and you know that you have a pretty good team in 2002, but such and such happens and we didn't get enough out of our talent. People have to be accountable."

That's why the 49ers can write off some of the Owens-Mariucci incidents. Owens is accountable. After a loss to the Rams in Candlestick, he sat at his locker for more than 90 minutes with his head covered by his hands. Owens dropped too many passes in that game. He felt accountable, and he worked harder to not repeat the bad game. Sure, Owens' outbursts created a distraction, but it didn't create problems with the chemistry of a team. Old Raiders teams bickered, but they won. Championship players occasionally come to blows in a locker room, but their accountability on the field dictates the direction of a team.

Study the dramatic changes taking place in Minnesota. Cris Carter's visual displays of anger at Randy Moss became a negative influence last year even though the two worked well enough together to go to two NFC championship games in three years. The problems started when Moss didn't run out every play and came out and said that he only had to play when he wanted to play.

Now that Carter is gone, Moss is a model of leadership. He's worked hard in the offseason. He leads by example on the field.

"Ask the New England Patriots and they will tell you the importance of chemistry," Moss said. "I don't think you can go out there as athletes without unity and win a championship. You have to play 16 regular season games like it's the last game."

The Dolphins made a tough decision this offseason. Defensive tackle Daryl Gardener has been one of their best defensive players for the past few years. Management made him one of the highest paid defensive tackles. Dolphins linebackers, mostly lighter than those on other teams because of Miami's emphasis on speed, managed their games around how Gardener and teammate Tim Bowens occupied blockers at the line of scrimmage.

	“	Ask the New England Patriots and they will tell you the importance of chemistry. I don't think you can go out there as athletes without unity and win a championship. You have to play 16 regular season games like it's the last game. ”
		— Randy Moss, Vikings receiver

But in the eyes of some Dolphins players, Gardener crossed the line of accountability. He was lax at showing up for meetings. Though he fought through horrible back problems that eventually required two surgeries, Gardener wasn't as accountable in past years on the practice field.

Whether Gardener was innocent, he was being found guilty in the locker room. The Dolphins cut him.

"It was more of a thing over the last three years, things got out of hand in certain situations," Thomas said. "I'm not trying to knock him. It wasn't his teammates who got him out of here. I didn't go upstairs to the coach and say to get rid of him. But if you want to be a leader on a team and you think he's slacking, I should tell him. And I've done that. The biggest thing is that no one in a locker room cares about the business off the field. You don't know what's messing with a guy's head. But when he's out there on the field, it doesn't matter if you hate the guy, everyone has to pull together."

Like most coaches, Dolphins coach Dave Wannstedt has a council of top veteran leaders whom he consults over team issues. During the offseason, Gardener wasn't as involved in the conditioning programs and his name kept cropping up in controversy. When Wannstedt asked his council, responses by the players were negative, and now Gardener is a Redskin

"Every team is going to have peaks and valleys, but the reason we won 11 games in each of the past two years is that when we've hit our valleys, we have bounced back real quick," Wannstedt said. "The only way you bounce back real quick is that you have a group of men who aren't pointing fingers and are willing to pull together and move forward to the next challenge. Every case is different. But as a head coach, you have to have the pulse of your football team nowadays, particularly because of free agency when you are constantly bringing in new guys."

One of the biggest problems a new coach has is weeding out the malcontents and slackers. Losing spawns complacency. With half of the league's head coaches turning over every two years, fixing chemistry issues is one of the first priorities.

"There is always a process you go through in taking over a new situation," Chiefs coach Dick Vermeil said. "Very few coaches get to take over a winning football team. There is reason's why they've been losing. You have to determine why they've been losing, whether it's players who have been paid well aren't playing well or those guys aren't good enough or the drafts not efficient enough. It's usually a combination of all those things. But frequently things disintegrate and you lose a squad because of morale and chemistry and then the next thing to go is the head coach."

Vermeil's biggest priority is setting tough, disciplined standards early and hoping the work ethic and chemistry follows. "You can't start soft and then get tough," Vermeil said.

But those teams that have recently won the Super Bowl have been strong on work ethic and high on accountability. Ray Lewis wouldn't allow slackers on his defense. Belichick set high standards for accountability. The list goes on.

Perhaps the most interesting chemistry challenge this season will involve Giant teammates Michael Strahan and Tiki Barber. Both are high character, hard working players, so their accountability should ward off major problems due to their public differences. Barber criticized Strahan for turning down the Giants $8 million-plus-a-year contract extension in February. Strahan took offense.

If the Giants win, there shouldn't be a problem. But if they lose ... Thomas, for example, doesn't think it's wise for a teammate to speak negatively about another teammate's contract negotiations. That could lead to troubles.

"You can be like brothers and sisters on a team," Jason Taylor said. "You are going to have your bickering. We have guys who bicker back and forth to each other, but 20 minutes later, they are hugging and getting a beer together. Players who have pride can have disagreements, but as long as you are accountable on the field, it works."

John Clayton is a senior NFL writer for ESPN.com.