Lions vs. Falcons: 3 things you need to know

The NFL's second of three London games this season, the Detroit Lions (5-2) take on the Atlanta Falcons (2-5) on Sunday in what will be an early kickoff for the North American crowd. The Lions will look to continue a hot start to the season that currently sees them tied atop the NFC North standings, while the Falcons will try to bring an end to a frustrating four-game losing streak.

Here are the three things you need to know:

Lions defense flying under the radar

For the past several season, the Lions' overall success has been tied to their high-powered offense. Now, while the offense struggles through some key injuries, it's the defense leading the way.

Heading into this year, few would have envisioned the Lions as the NFL's second-ranked scoring defense, but that's just what they are through six games.

The Lions' strong defensive front is making its presence felt in all phases of the game, both winning the line of scrimmage against the run and consistently pressuring the quarterback in the passing game.

Having similar success this week against a thin Falcons offensive line would go a long way toward limiting what can be one of the NFL's most dangerous down-field passing attacks, and that matchup should have a significant bearing on the outcome of this game.

Falcons' passing game not enough

Led by quarterback Matt Ryan, the Falcons' passing game is once again one of the NFL's most productive units on the offensive side of the ball.

To this point in the season, however, it hasn't been enough to overcome the many areas the team is struggling in elsewhere on the field, as the Falcons enter this game with the NFL's 23rd-ranked running game and the 30th-ranked overall defense.

As productive as the passing attack can be at times, with Ryan, Julio Jones and Roddy White playing at a high level seemingly no matter the opponent, the Falcons won't enjoy any consistency if they can't improve in some other key areas of the game.

Doing so Sunday against the Lions is certainly a tall task, but would go a long way toward establishing some much-needed momentum heading into the bye week.

Calvin Johnson still working toward return

Although the Lions' offense came through late in last week's comeback win over the New Orleans Saints, it's a completely different unit without its best player, Calvin Johnson, on the field.

Working his way back from a high ankle sprain, Johnson has began to run again and did travel with the team to London, but whether or not he has a chance to play this week remains to be seen.

Facing off against a Falcons defense that is surrendering 274.4 passing yards per game, the Lions may be able to move the ball well either way, but Johnson returning to the lineup would make the matchup all the more favorable.