NFL Playoffs 2012: Previews of the AFC, NFC Championship Games

Two of the teams playing this weekend were supposed be here, two weren't.

Before the season, the New England Patriots and Baltimore Ravens both figured to be contenders. Here they now stand, the top two teams in the AFC and one win from the Super Bowl.

On the NFC side, the New York Giants and San Francisco 49ers surprised two of the NFL's hottest teams to get to this point.

Both championship games offer a variety of intriguing storylines.

New York Giants vs. San Francisco 49ers

 The Giants have peaked at the right time and are currently playing their best football of year. They dismantled the Green Bay Packers last week and now they travel across country to face the Niners.   

San Francisco, meanwhile, has been steady all year. It proved that again Sunday by beating the red-hot New Orleans Saints.

These teams match up very well and it should be an even matchup on Sunday.

When the Giants have the ball

The Giants offense has been brilliant in recent weeks.

Since their Week 15 loss to the Washington Redskins, the Giants have averaged more than 30 points per game. Also, quarterback Eli Manning has been near flawless. In the last four weeks, Manning has thrown for 1,178 yards, 10 touchdowns and two interceptions.

It's crucial the Giants protect the football this weekend. The opportunistic Niners defense forced the Saints into five turnovers last week, which can't happen this week for the New York.  

As impressive as Manning has been recently, the Giants' third-down conversion rate my be more impressive. New York converted 50 percent (8-of-16) of its third downs against Green Bay and 53 percent (8-of-15) against the Atlanta Falcons.

The Giants' ability to extend drives has kept some very good opposing offenses off the field. It has definitely been one of the big keys to their late-season success.

The Giants will face a tough task against the Niners to keep that third-down success going. The Niners allowed the Saints to convert just five of 14 thirds, and New Orleans was one of the best third-down teams in the NFL this season.

The team that wins on third down may very well win this game.

When the 49ers have the ball

Alex Smith had his best game of the year last week, throwing for 299 yards, three touchdowns and zero interceptions. He also scored a rushing touchdown late in the game. However, Smith will need to be even better this week against a very good Giants defense.

Last week, the Giants' pass rush was relentless and Aaron Rodgers never got comfortable in the pocket. New York's ability to get pressure on the quarterback from its front four is the key to its defensive success.

As explained in an article by Bleacher Report's James Dudko, the Giants used a variety of schemes to rattle Rodgers. Expect defensive coordinator Perry Fewell to design more unique defensive looks to confuse Smith. 

The Niners will try and counter the Giants' aggressive approach by running the ball with Frank Gore. A successful running game will keep the Giants' defense honest and their offense on the sidelines.

However, the Niners must do a better job of converting third downs. San Francisco struggled to convert third downs Sunday, moving the chains just 27 percent (4-of-15) of the time. The key for the Niners is to stay on schedule and avoid third-and-long situations.    

Look for San Francisco to find ways to continue to get the ball to Vernon Davis. He's coming off a monster game where he caught seven passes for 180 yards and two touchdowns, including the game-winner. Davis should find plenty of room against a defense that yielded a team-high nine targets to Packers tight end Jermichael Finley.

Baltimore Ravens at New England Patriots

The Patriots look like they're the team to beat this postseason. They boast a juggernaut of an offense, while their defense continues improving. They destroyed the Denver Broncos last week and now they will host the Ravens.   

Baltimore, meanwhile, has been a difficult team to figure out this year. They've lost games they shouldn't have and they looked very average against an undermanned Houston Texans team last week.    
Despite being the No. 1- and 2-seeded teams in the AFC, there is significant disparity with these two teams heading into Sunday.

When the Patriots have the ball

The Patriots are masters at exploiting mismatches. Whether it's Tom Brady throwing to his tight ends or Wes Welker catching 15 passes, they're a nightmare for defenses.

Brady is playing at an extremely high level, and covering tight end Rob Gronkowski has proved to be impossible. The duo connected on three touchdown passes Sunday against the Broncos, giving Gronkowski 21 TDs this year.

Like most defenses, the Ravens don't have the personnel to match up with Gronkowski or the Patriots' other tight end Aaron Hernandez. That dilemma will force Baltimore to be more aggressive.

The Ravens have an attacking defense that is designed to disrupt pocket passers like Brady. However, that aggressive defense was held without a sack last week against rookie quarterback T.J. Yates.

It's crucial the Ravens pressure Brady. If they don't, he'll pick them apart just like he did the Broncos.

When the Ravens have the ball

While most of the attention this week will be on quarterback Joe Flacco, the key to the Ravens offense is Ray Rice. Baltimore must get Rice involved in the early and often.

In Baltimore's 13 wins this season, including the playoffs, Rice has averaged 97 rushing yards per game. In the four losses, he averaged 38 rushing yards per game.

While Rice wasn't the reason the Ravens won last week—it was their defense—he's significantly important to their success. If Rice can chew up yards and keep grinding out first downs, Flacco should be able to find Anquan Boldin running open in the middle of the field.

Flacco must also show a willingness to take shots down field. Rookie Torrey Smith's speed and big-play ability could play an important role in changing field position and creating momentum for the Ravens.

Lastly for the Ravens, they have to win the turnover battle. They cannot afford to give the Patriots offense more possessions. Baltimore did a great job against the Texans, not turning the ball over once. 

As for New England's defense, it's starting to make plays when it needs to. Last week, the Pats had five sacks against Denver and held the Broncos to just 252 total yards and 10 points. And in the last four games, New England has 10 takeaways.

Sure, it's giving up a lot of yards, but right now it's playing bend-don't-break defense.