The 2013 Super Bowl is expected to be highly contested.

The San Francisco 49ers are just 3.5-point favorites over the Baltimore Ravens, a team that has won three straight playoff games.

Both teams are well-rounded, but a few players could be the difference in who takes home the Vince Lombardi Trophy. Colin Kaepernick is listed as the favorite to win the MVP award at most sportsbooks, with Joe Flacco right behind him. The starting running backs also have good odds of winning the award.

Here are five players that will have the biggest impact on the outcome of Super Bowl XLVII.

Joe Flacco

Flacco is the biggest reason why the Ravens have a chance to win their first Super Bowl in 12 years. After being carried by a dominant defense for much of his career, the quarterback has been the team’s best player in the playoffs.

Over the past two years, the 49ers have been the best defense in the NFL. San Francisco is able to stop the run and the pass. However, they have been susceptible to big plays, of late. Flacco has not been intercepted on passes of at least 20 yards, and will have to continue that streak in order to give the Ravens a chance of picking up the win.  

Colin Kaepernick

Even with Flacco’s 114.7 passer rating in the postseason, it’s hard to argue that anyone has performed better in the playoffs than Kaepernick. His 181 rushing yards against the Green Bay Packers set a record for quarterbacks, but his 127.7 passer rating against the Atlanta Falcons proved that he can be dominant through the air, as well.

Since replacing Alex Smith, Kaepernick has brought a new dynamic to the 49ers offense. Along with an elite defense and a great running game, San Francisco can beat teams by throwing the ball down the field. When the first-year starter plays up to his capabilities, it becomes extremely difficult for any team to match up with San Francisco.

Ray Lewis

Other than the Harbaugh brothers, the biggest story of Super Bowl XLVII may be the retirement of Lewis. Sunday will be the final game of the linebacker’s NFL career, and he’s looking to end his playing days on a high note.

He’s no longer the dominant force he once was, but Lewis is still leader of Baltimore’s defense. He missed 10 regular season games, and the team allowed an average of four more points per contest when he wasn’t on the field. Lewis doesn’t have to give an MVP-like performance as he did in 2001, but it’s important that he disrupts the 49ers offense and prevents Kaepernick from recording any long runs.

Aldon Smith

For much of the 2012 regular season, Smith was in contention to win the Defensive Player of the Year award. He recorded 19.5 sacks in the first 13 games and was on pace to break Michael Strahan’s record.

Since Week 14, Smith has not gotten to the quarterback. San Francisco’s defense has suffered, allowing at least 30 points in three of their last five games, something they never did in the previous 13. He’s a major part of the 49ers pass rush, accounting for half of the team’s overall sacks.

Smith needs to put pressure on Flacco, and make it difficult for him to complete long-pass plays.

Justin Smith

The defensive lineman may not have the gaudy numbers of Aldon Smith, but he’s just as important to the 49ers success on defense. He’s one of the top players at his position with his ability to both stop the run and rush the passer.

Aldon Smith’s performance, as well as the rest of the team’s defense, began to decline when Justin Smith suffered an injury. He’s not completely healthy, but the 12-year veteran’s production is a key to keeping Flacco and Ray Rice at bay.