The Dolphins have the NFL's No. 1-ranked rush defense, limiting opponents to 61.4 yards per game. Tyler Barrick/Getty Images

This is a full-accountability blog here in the AFC East. Therefore, I will be the first to admit that I did not expect much from the Miami Dolphins this season.

"This is a rebuilding year for the Dolphins. There are too many changes all across the board for Miami to be a legitimate threat," I wrote in Miami’s 2012 season preview on ESPN.com.

I also explained in the preseason why I thought Miami would finish last in the AFC East and would be hard-pressed to surpass last year's 6-10 record. The lack of offensive firepower and playing a rookie quarterback with only 19 college starts was too much to overcome to win right away. The defense gets the hype of a top-10 unit but was somewhat overrated, I proclaimed.

But five games into the season, I'm already starting to eat those words. Therefore, it is time to raise expectations in Miami.

The Dolphins are a pretty solid football team. They're certainly better than most pundits, including the AFC East blog, projected.

Miami is playing complementary football, and rookie quarterback Ryan Tannehill is developing faster than expected. The combination has led to a 2-3 record, which includes back-to-back overtime losses to the New York Jets and Arizona Cardinals. Barring a few missed field goals by struggling kicker Dan Carpenter, Miami could be 4-1 and in first place in the AFC East.

Rookie QB Ryan Tannehill has been playing well enough that the Dolphins could be a .500 team. Kirby Lee/Image of Sport-US Presswire

If the Dolphins remain focused, they could be in position to be one of the surprise teams by the end of the season. It starts Sunday with a huge home game against the St. Louis Rams (3-2). The Dolphins have a chance to get back to .500 heading into their bye week.

After that, anything is possible for this hungry, blue-collar group.

"I think if you watch our film, you’d have to say that we've played five games and I think our guys have been ready to play five times," Dolphins rookie head coach Joe Philbin said proudly this week. "That's a good place to start. ... I like the fact that they've been competitive and, aside from five minutes in the Houston game, [were] in every single game we've played. Those are good starting points and hopefully we can build off of that."

The Dolphins are establishing a foundation for the long run. It starts with Tannehill, who doesn't get the rookie quarterback hype of Andrew Luck or Robert Griffin III, but the No. 8 overall pick has the same number of wins. Tannehill's arm and poise have raised the level of Miami's offense. The Dolphins are eighth in the league in rushing, and Tannehill can make all the throws when opponents load the box. Miami's defense also is No. 1 against the run, allowing just 61.4 yards per game. The pass defense still needs work but appears to be improving.

The reigning AFC champion New England Patriots (3-2) are still the class of the division. But overall, this is another down year in the AFC East.

The Buffalo Bills (2-3), my sleeper pick for 2012, have talent but can't seem to put it all together. Former Pro Bowl defensive end Mario Williams hasn't lived up to his $100 million contract, and the defense overall has drastically underachieved. Bills quarterback Ryan Fitzpatrick also has been too streaky for Buffalo to win consistently. Buffalo has lost two straight games by an average of 33 points and faces a lot of questions about its toughness.

The New York Jets (2-3) have too many significant injuries and in-house issues to be a playoff team. New York lost its best defensive player (Darrelle Revis) and offensive player (Santonio Holmes) within a two-game span. Quarterback Mark Sanchez has not performed well with Tim Tebow pushing him. Sanchez has a career-low 48.4 completion percentage and appears a bad game or two away from losing his job. New York is averaging just 12.5 points in its past four games, and the defense is 20th in the NFL and not the dominant group most expected. The Jets have too many leaks in their fast-sinking ship.

The rebuilding Dolphins are the 2-3 team in the division that most has it together. Why wait for next year when Miami can be a threat now?

"No doubt, the Dolphins are clearly the second-best team in the division for me," said Matt Williamson of Scouts Inc. "They have a quarterback. Tannehill is much more talented and accurate than Sanchez and Fitzpatrick. Tannehill also has far better pocket presence."

It's also a down year in the conference. Outside of the undefeated Houston Texans (5-0) and Baltimore Ravens (4-1), no AFC team is separating from the pack in the first half of the season. There are eight teams in the conference with 2-3 or 3-2 records. The Indianapolis Colts also are 2-2 after an early bye week. The two wild-card spots in the AFC are wide open.

Any of these nine teams could step up and be in contention by the end of the season. So why not the Dolphins? Miami has a relatively easy schedule and is a tough out against most teams.

The Dolphins can run the football and stop the run. That is a formula for frustrating opponents. As Tannehill continues to grow with the passing game, the Dolphins will be even more dangerous.

Before the season, I thought a 6-10 record would have been a success for these Dolphins. But that is no longer the case.

I have seen enough in the first five games to expect more from Miami. Anything fewer than eight wins would be a disappointment considering the way the Dolphins are playing and how the Bills and Jets are falling apart.