NFL Playoffs 2012: Teams with First-Round Byes That Should Be Worried

It's all fine and dandy to earn a first-round bye in the NFL playoffs.

In fact, teams should be proud of such an accomplishment.

But that doesn't mean these teams are invincible, nor does it exclude potentially losing momentum with an extra week of rest.

The Baltimore Ravens and San Francisco 49ers are two teams with first-round byes who should be most worried after their first-round byes.

Baltimore Ravens (12-4)

The Ravens lost to the San Diego Chargers in Week 15, then they won by a combined 14 points against the Cleveland Browns and Cincinnati Bengals.

This defense is still one of the top units in the NFL, but I have concerns about the offense and this team's consistency...or lack thereof.

The Ravens have a top quarterback in Joe Flacco, top running back in Ray Rice and two strong receivers in Anquan Boldin and Torrey Rice. But they go through prolonged funks offensively that just boggle the mind.

The Ravens, despite being 12-4, don't resemble a 12-4 team.

San Francisco 49ers (13-3)

The 49ers are 13-3 this season, but they've rarely dominated opponents, which in part has to do with their offense.

Rookie head coach Jim Harbaugh has been a big part of this team's success, getting virtually the same offense to perform above all expectations. Still, this isn't a team that is going to blow good defensive teams out of the water. That generally makes their games close.

On top of that, the defense almost let the team down in Week 17, allowing the bumbling St. Louis Rams to score 17 points. What if that defensive performance carries over into the playoffs?

There's also the issue of momentum and continuity. A lot of this team's success has been because they've built a chemistry that is challenged by few teams in the NFL. What happens with an extra week of rest? Will they have the same edge or flow, both offensively and defensively?

49ers fans have a right to be ecstatic right now after years of mediocrity, but the real test comes in the playoffs.