How important can a game be in only Week 6 of the season? For the Denver Broncos and the Miami Dolphins, who meet Sunday night (ESPN, 8:30 p.m. ET), all they need to do is look at their divisions.

In the AFC North, an 8-8 or 9-7 record could win the division. The same thing could happen in the AFC South. But in the Dolphins' AFC East and the Broncos' AFC West, it may take 10-12 wins to claim first place. And with only two wild-card berths available in each conference, more of a premium is placed on winning the division. Otherwise, teams could be left out in the cold despite having a great season.

Theismann's keys

MIAMI DOLHPINS Offense -- Run, Ricky, run: Williams has to continue running to keep the pressure off Jay Fiedler. He may not run 36 times, as he did last week. Williams only gained 105 yards (2.7 a carry), but the key was the Dolphins had the ball for 40 minutes. Turnovers created those opportunities. It may be a similar approach Sunday. Miami wants to control the ball and keep Denver's offense off the field. If the Dolphins can run the ball in a hostile environment, they can take the Denver crowd out of the game. It will be difficult against Denver's run defense, but Miami must run to do what it wants to do offensively. Defense -- Let Griese win it: The Dolphins need to force the ball into Griese's hands and make him throw the football. They need to keep wraps on Rod Smith, who has yet to have a spectacular day. Ed McCaffrey is coming up with big plays, but Miami must be conscious of Smith's home-run ability. DENVER BRONCOS Offense -- Pound with Portis: The Broncos must establish some type of a running game to take the heat off Griese. They need to balance their attack enough so they can run the ball effectively. If they can run for 110 yards on 30 carries, that would be a good day for the Broncos' offense. Defense -- Stop Ricky: If Denver stops Williams, it can stop Miami. I don't think the Broncos should drop eight men in the box because Chris Chambers is a quality receiver. O'Neal may have to handle him, making for a great matchup outside.

It's critical for the Broncos and the Dolphins, two of the AFC's best teams, to keep winning and to stay near the top of their divisions. Both teams are coming off huge divisional victories -- Denver over San Diego and Miami over New England -- after suffering bad losses to Baltimore and Kansas City, respectively.

Looking at the Broncos' schedule through the first five weeks, if I had to pick one team I thought they would beat, it would have been Baltimore. I could have understood a loss to any other team. In fact, I look at the Denver-Baltimore game as almost an aberration. I don't even think the Ravens would have believed they could win 34-23.

The Broncos are now among the league's best defensively under coordinator Ray Rhodes. Now in his second year, Rhodes has gotten to know the players, and the players have gotten to know what he wants. The more comfortable and familiar the players and coordinator are, the better off they are.

The linebacking corps is fast, and the defensive line is big and productive. Chester McGlockton has settled in as a force at defensive tackle, and Trevor Pryce has moved to end, where he can give them some speed off the edge. Keep in mind that Denver, which has the NFL's No. 2 run defense, hasn't given up a 100-yard rusher in its last 18 home games, so the Broncos have something at stake against Ricky Williams.

Deltha O'Neal has made a big difference in what the Broncos are able to do. Not only is he a great return man, but he has also done an excellent job at cornerback. His only mistake was bumping the official in the Baltimore game. It turned out to be a bad situation, one that got him ejected and cost Denver.

Although their defense has carried them, the Broncos have built a reputation as an offensive team under head coach Mike Shanahan. And now the offense is beginning to play better. Quarterback Brian Griese has met the challenge after entering the season on the hot seat and had a big game against the Chargers.

Rookie Clinton Portis seems to have settled in nicely as the No. 1 running back. Nobody knew what to expect when Terrell Davis' injuries forced him to retire, but Portis has given the Broncos a nice complement to Olandis Gary.

Denver lacked a solid fullback since Howard Griffith retired. Don't underestimate the impact of a good fullback; look at Griffith in Denver, Sam Gash in Baltimore and Tom Rathman in San Francisco as a few examples. But Mike Anderson is a team player who understands his role, as do the other backs.

In Miami, head coach Dave Wannstedt hitched his wagon to Ricky Williams. The Dolphins made a decision to get Williams and felt a quality running back was what they needed to have a shot at the championship. Last season Lamar Smith's longest run from scrimmage was 25 yards. Williams has already had three runs over 25 yards in five games.

But the best offseason acquisition -- for both teams -- was Norv Turner, Miami's offensive coordinator. Turner has once again proven how good an offensive coach he is. Look at the production he gets from his running backs, quarterbacks and receivers. And then there is the tight end position. He had Jay Novacek in Dallas and Stephen Alexander in Washington. Now Turner has Randy McMichael, a fourth-round pick who looks like a steal with 16 catches, three for touchdowns.

Last but not least, the Dolphins' defense has been typically solid. We have come to expect great things each year from Miami's defense. And the Dolphins have been great aside from the Chiefs' game, when they allowed 48 points and 450 yards. I get a kick out of a comment from Zach Thomas, who said the Dolphins used to win games in the fourth quarter. Now they have a chance to win and control games in the first and second quarter. That comment came as a tribute to how well the Dolphins' offense has played this season compared to past years.

Looking at both the Broncos and the Dolphins, it's tough to emphasize one particular area of either team. That indicates how solid and complete the two teams are. When two evenly balanced teams play, the return game becomes even more critical for field position, for changing momentum and for creating scoring opportunities. In other words, the Dolphins and Broncos are looking for many happy returns Sunday night.

Former NFL quarterback Joe Theismann is an NFL analyst on ESPN Sunday Night Football.