The Houston Texans' team numbers this year are staggering, as they rank 1st in points per game and 2nd in opponent points per game. Their offense has the least turnovers in the league, and they have some great weapons in Andre Johnson and Arian Foster. They rank 2nd in pass defense and 11th in rush defense, though they rank 23rd in opponent yards per carry.
The team has not been faded by the loss of Mario Williams, as their defense continues to dominate thanks to Brian Cushing, Johnathan Joseph, and JJ Watt, who has 7.5 sacks and five batted passes already. When the offense is healthy, they have a ton of firepower with Matt Schaub, Foster, and Johnson - all of whom dealt with injuries at some point last season.
Something to consider when looking at the Texans' exceptional league ranks, however, is that they have played three teams that are 1-3. The combined record of their opponents is 5-11. The only team they have played that is considered a remote threat to make the playoffs is the Broncos, who the Texans beat by only six points.
Where the Texans were exceptional in league rankings, the Atlanta Falcons were not far behind. The Falcons high powered offense ranks 3rd in scoring, while they also possess the league's 8th best scoring defense. Just like the Texans, the Falcons' offense has the least turnovers in the league, and both teams beat the Broncos by six. Michael Turner leads a Falcons' rushing attack that averages 4.1 yards per carry - the best of the undefeated teams. The biggest weakness for Atlanta is their rush defense, which is ranked 29th and gives up the second most yards per carry.
The Falcons schedule has been significantly tougher than the Texans. Though their opponents' combined record is only 7-9, most would agree that it's much harder to remain undefeated playing against the Chargers and Panthers than against the Dolphins and Jaguars.
Finally, we have the Arizona Cardinals, who have burst on the scene with a dominating defense and a solid offense. They're only 16th in scoring offense, but are 3rd in scoring defense with the 4th most takeaways in the league. The problems with this team, however, is that they are only 15th in giveaways and average only 2.7 yards per carry. When your team is anchored by a strong defense, you usually want to compliment it with a strong rushing attack.
As far as wins and losses, the Cardinals have had the toughest schedule of the undefeated teams. Their opponents have combined for an 8-8 record, but that includes a win by the Seahawks over the Packers, so many people - especially those in Green Bay - would say their opponents' record should be 7-9. However, you can't discredit the Cardinals for two exceptionally impressive victories, as they beat the Patriots in New England and dominated the Eagles at home.