NFL Power Rankings: Biggest Movers from Sunday's Week 1 Action

Who would have thought that radically altering a losing franchise in the offseason or bringing back your head coach could have such positive effects?

With the amount of parity in the league, the margin for error is incredibly small. One personnel move can turn you from an also-ran into a postseason contender. You also cannot plan too much for the long term. A team's window can last only a few seasons, so you need to strike while the iron's hot.

There were plenty of teams who had disappointing 2012s, only to attack the offseason with a purpose. They determined their weaknesses and made the necessary moves to get better. The results could pay major dividends.

Here's where each team ranks after Sunday, followed by three losing teams from 2012 that got the biggest boost from their wins.

No. 7 New Orleans Saints

The New Orleans Saints are undoubtedly back. With Sean Payton returning from suspension, the team has picked up right where it left off in 2011. Last season was a bit of an aberration, as any NFL team would be much worse off without its head coach.

In what is an uber-competitive NFC South, beating the Atlanta Falcons is a major marker for the rest of the season. The circumstances with this win are a little different than the Saints' win at home last year, so there's much more reason to be encouraged by the result if you're a Saints fan.

New Orleans' defense wasn't stellar, but it stepped up at the right moments and held the Falcons to just 3-of-11 on third downs. The standout performer was rookie Kenny Vaccaro. He had five tackles and knocked the ball away on Atlanta's Hail Mary attempt at the end of the game.

No one is doubting how good Drew Brees can be this season. The bigger variable is that defense, and if it can continue playing like it did in Week 1, this is a dangerous team.

No. 15 Kansas City Chiefs

Let's not get too worked up about a win over the Jacksonville Jaguars. It's almost like beating a college team. The Jaguars are an absolute mess, especially when it comes to the passing game. To the Chiefs' credit, they didn't give Jacksonville any opportunity to sneak a win. Kansas City controlled this game from start to finish.

Alex Smith did exactly what you would have expected. He wasn't flashy, but he got the job done, with 21-of-34 passing for 173 yards and two touchdowns. Smith didn't turn the ball over and managed the game perfectly.

The encouraging sign was the pass defense, which has improved a lot with Dunta Robinson and Seth Smith in the fold. The Chiefs intercepted Blaine Gabbert twice, one of which was taken back for a touchdown.

The AFC West belongs to the Denver Broncos. There's a good chance Kansas City could get a wild-card berth. The AFC East isn't a deep division, while the AFC North really looked bad, with all four teams getting Week 1 losses.

No. 19 Miami Dolphins

Turns out if you spend a boatload on your passing game in the offseason, it makes a major difference. The Miami Dolphins made a big investment in Ryan Tannehill when they re-signed Brian Hartline and bringing in Mike Wallace and Brandon Gibson as free agents.

After the win against the Cleveland Browns, Hartline has already matched his 2012 total for receiving touchdowns. He had a big game, catching nine passes for 114 yards and a touchdown. Gibson also had seven receptions for 77 yards. It didn't matter Wallace only had one catch for 15 yards.

The Dolphins were just good as good on the defensive side of the ball. They forced Cleveland into making three turnovers and sacked Brandon Weeden six times.

Don't sleep on Miami this year. There's little chance it can challenge the Patriots in the AFC East. However, the Dolphins could challenge for a wild-card spot.