MIAMI GARDENS, Fla. (AP) — Six weeks into their season, and 13 weeks after training camp opened, the Miami Dolphins begin playing the games that matter most.

The Dolphins (3-2) face an AFC East rival for the first time Sunday when they take on the Buffalo Bills (2-4). Miami is the last team in the conference to play within its division.

"Division games are the ones you look forward to, the ones that you want to win the most," quarterback Ryan Tannehill said. "You play each team twice, and in order to win your division, the best way to do it is to win the games in your division. We have them all right in front of us, so I feel like that's an advantage for us."

That's true only if the Dolphins fare better than they have in recent seasons against their biggest rivals. They're 20-34 versus AFC East teams over the past nine years, which is a big reason they've made playoffs only once in that span.

And they've repeatedly come up short against Bills teams perceived as pushovers. Since the start of 2004, Buffalo is 10-8 against Miami and 49-83 against everyone else.

As the rivals prepare to meet for the 99th time, here are five keys to watch in the game:

MIAMI TRIES TO TAKE CARE OF BUSINESS: The Dolphins survived the toughest part of their schedule well-positioned for a playoff run. They've lost two in a row, but the defeats were against NFC South leader New Orleans and defending Super Bowl champion Baltimore.

Now they're coming off a bye and likely will be favored in five of their next six games.

Any projected scenario sending the Dolphins to the playoffs would include a win Sunday, especially with Buffalo riddled by injuries. Most calculations of paths to the playoffs for Miami would include two victories against the Bills and two over the division rival Jets.

"Winning teams win games like this," Dolphins tackle Tyson Clabo said.

"Division games are worth two," teammate Brian Hartline said. "You give them a loss; you give yourself a win. It's like a two-point swing. That's the magnitude of the game."

Buffalo is 0-2 this year against division opponents, and 6-26 since 2008 — but three of those victories have come versus the Dolphins. And despite their injuries, young roster and new coaching staff, the Bills have exceeded expectations so far.

"That probably shows how poorly it has been before," first-year coach Doug Marrone said.

The Bills have been within a score of their opponents in the fourth quarter of each game, including last week's overtime loss to Cincinnati.

BUFFALO QB RETURNS HOME: Thad Lewis, Buffalo's interim starting quarterback, grew up near the Dolphins' stadium and remembers rooting for the home team when Dan Marino and the Bills' Jim Kelly would trade touchdown passes.

"Those were the great old days," Lewis said.

Buffalo's passing game is less potent now, but Lewis came to the rescue last week. After being promoted from the practice squad, he overcame a sprained right foot and a 14-point deficit, throwing for two fourth-quarter touchdowns against the Bengals.

He's expected to start again Sunday while rookie EJ Manuel recovers from a sprained right knee.

"You want to show everyone that you belong in this league, so you have to play great week in and week out no matter what the situation is, once you get the opportunity," Lewis said. "I never know what my future holds with the Bills, but I just know I am going to give it my best shot while I am out there."

CONTRASTING GROUND GAMES: Running the ball is what the Bills do best, and what the Dolphins do worst.

C.J. Spiller and Fred Jackson are each on pace to approach 1,000 yards rushing, and the Bills rank third in the NFL with an average of 149 yards per game.

"They have two very, very productive backs," Miami coach Joe Philbin said. "It's going to be incumbent on us to get off of blocks, tackle well, pursue well — certainly nothing magical."

The Bills would love to play keepaway against the Dolphins, who are averaging less than 70 yards rushing per game. At that rate Miami will break the 25-year-old franchise record for fewest yards rushing in a season.

Facing Buffalo might be what the Dolphins need to get their ground game going. The Bills have allowed more than 150 yards rushing three times this season.

BLOCKING FOR TANNEHILL: Miami's offensive linemen are attracting lots of publicity, and they know that's not good. The reason for their notoriety: Tannehill has been sacked 24 times, most in the NFL.

His total includes at least four sacks in every game, and that streak might be difficult to end against the Bills, who began the week ranked third in the NFL with 21 sacks. Mario Williams ranked third with eight.

BILLS SEEK ROAD BREAKTHROUGH: To end a streak of five consecutive last-place finishes in the AFC East, the Bills must start playing better on the road. They've lost 15 of their past 17 away games, including the past six , and they're 0-2 this year, with losses at the Jets and Browns.

Seven of Buffalo's final 10 games are away from Orchard Park.

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