After a rough opening week loss to the Tampa Bay Buccaneers, the Atlanta Falcons have righted the ship.

Quarterback Matt Ryan is playing at a high level, receiver Julio Jones is coming off a record setting game where he caught 300 yards worth of passes, and the team just beat up on what was supposed to be a good Carolina Panthers defense.

The Atlanta Falcons are in control of the NFC South and look like they could be a very good team.

But are they?

This is not a team without weaknesses and they could be in for a rude awakening against the Denver Broncos defense.

Three out of the first four teams the Falcons offense has faced have been pretty bad defenses. The Tampa Bay Buccaneers is rated as the No. 21 defense according to Football Outsiders’ DVOA metric (actually 25 versus the pass), with the Oakland Raiders even worse at 29 (28 versus the pass), and the New Orleans Saints just behind them at 30 (27 versus the pass).

The Panthers were a tougher challenge, ranked No. 6 overall, and tenth against the pass, but they were truly the best defense this team has faced and head coach Ron Rivera and his staff showed a shocking unwillingness to adjust in-game.

That’s not to take anything away from the Falcons, but anyone could have seen that maybe this team should have covered Julio Jones more tightly.

Aside from Carolina though, this offense has picked on some pretty mediocre—and in some cases, awful—defenses. It’s hard to get a read on the overall quality of the offense when their opponents aren’t quality themselves.

Taking Ryan and Jones out of the equation—and again, allowing for the quality of opponents—the ground game seems to have found its feet and that’s a very dangerous thing for the opposition. While Devonta Freeman didn’t have a great day from a yards perspective, he scored his first rushing touchdown (second touchdown of the year overall), and has rushed for 302 yards in the last three games.

When Freeman isn’t on the field, Tevin Coleman is, and even if he doesn’t run the ball as well or as often, he is still dangerous. Coleman was quiet against Carolina, but scored four touchdowns in the previous two games. Freeman can be a “home run hitter” while Coleman is dangerous in short yardage situations.

Naturally, their offensive line loves them.

“I think they both are really good and make the offensive line look really good,” center Alex Mack told Vaugh McClure of ESPN. “I’m really happy about it. Our whole team is fighting to get those couple extra yards, and the running backs are turning those couple extra into a lot.”

The biggest change offensively is philosophical though.

Whereas last season offensive coordinator Kyle Shanahan forced Ryan to do a lot of bootlegs and rollouts this year it’s a different look, one which plays to his quarterback’s strengths. Turns out, it works and works very well.

What a concept.

Now here’s where this can all go wrong.

The Atlanta Falcons defense is awful.

There is no metric to make it look good. Football Outsiders has them ranked as the worst in the NFL, No. 32 overall, 31 versus the pass and 29 versus the pass. They have allowed the second most yards through the air (1,268), allow an average of 317 passing yards a game, have given up the most passing touchdowns in the NFL so far (13) while generating only four interceptions.

They have allowed 409 yards on the ground (a middle of the road 17^th in the NFL) but average 4.5 yards per carry against (fifth worst) and allow 102 yards a game on average. Of course, some of those stats tell only part of the tale, since only eight other teams have been run on less than the Falcons.

So far, the Falcons have won shootouts. They’ve scored more and outlasted other offenses, and managed to come away with wins. They are averaging 31 points allowed per game and have given up a grand total of 124 points overall so far.

The only teams who have allowed more points are the Tampa Bay Buccaneers, Indianapolis Colts and New Orleans Saints, whose collective record is 3-9.

That is not a great sign.

This Falcons team reminds one of the Saints during the first few years with Drew Brees. No defense, but lots of firepower on offense. The Saints were quicker on the draw, and they won a lot of games.

Eventually though, like gunfighters in the old west, the Saints found out there are always people who are quicker. Eventually you get old and someone out-draws you.

That’s the biggest concern for this Falcons team as well. They have a potent offense, but they sit on a razor’s edge.

One slip—one fraction of a second too slow on the draw—and they could find themselves stumbling.

This is a good team, but it’s flaw is a big one and could be fatal in the pursuit of a Super Bowl.