Alex Smith, Kansas City Chiefs.

For the second time in his NFL career, Alex Smith will take the helm of a team that is in a rebuilding mode. He will hope for a better start than his last go around.

Considered a bust by many, Smith proved to be a more than capable NFL quarterback with the arrival of Jim Harbaugh in 2011, leading the team to its first playoff appearance in almost 10 years. However, an injury and the emergence of the electric Colin Kaepernick would relegate Smith to the bench despite leading the team admirably in the opening half of the season.

Now with a new home in Kansas City, Smith will have to prove himself yet again as a capable NFL starting quarterback. The Chiefs' offense will be expecting a lot out of him, just as the 49ers were. With an above average offensive line, an ideal target in Dwayne Bowe, and a running game capable of covering for him, everything is in place for Smith to succeed, but will he?

Christian Ponder, Minnesota Vikings.

Ponders’ career has seen its share of ups and downs and it nows looks as if the 2013 season will be his make or break year. Having been practically rushed into the starting lineup in his rookie year, Ponder showed glimpses that he is capable of being the team’s franchise quarterback, but by the end of the season that was all but forgotten after an incredible series of errors.

Much was expected of Ponder, perhaps unfairly, and he has yet to truly prove himself to the Vikings faithful. If he is able to post decent numbers, reduce the number of baffling mistakes from the last year, and let Adrian Peterson do his job, Ponder should be able to win the confidence of his team's fans. If not, the Vikings will soon be on the lookout for yet another franchise quarterback.

Phillip Rivers, San Diego Chargers.

After producing three stellar seasons as the successor to Drew Brees, Phillip Rivers is now facing the more pressure than ever as the Chargers number one signal-caller.

It’s been three seasons since the Chargers, once considered the most talented team in the NFL, have been to the playoffs, and part of that can be attributed to River’s waning level of play. True, an atrocious offensive line has been a major part of River’s decline, but his number of interceptions over the last two years (35) and his mental mistakes have cast doubt on his future with the team. Rivers will get a fresh start under new head coach Mike McCoy, who has tried his best to fix the team’s offensive line and given Rivers more weapons to work with.

If Rivers wants to step out of the shadow of his 2004 Draft classmates Eli Manning and Ben Roethlisberger, who each boast a pair of Super Bowl rings, he will have to at least lead the Chargers back to the playoffs this season.

Tony Romo, Dallas Cowboys.

Like the Chargers, the Cowboys were once considered among the league’s best but have not seen the playoffs in three years, and some of those failures can be blamed on Tony Romo.

While Romo has been able to post strong numbers over the past seasons, fans are quick to point out his eternal struggles in the 4th quarter as the reason why the team has lost so many games, both in the regular and postseason. Despite his failure to deliver in the clutch, the team opted to reward Romo with a six year, $108 million extension. No one will question Romo’s natural talent and ability to put up numbers, but if he continues to come up short in games where his team needs him most, Cowboys owner Jerry Jones may regret investing so much in a quarterback with just a single postseason victory in his entire career.

Blaine Gabbert, Jacksonville Jaguars.

The list of the Jaguars' first round misses will grow a bit longer if Blaine Gabbert is unable to turn things around this year.

The Jaguars made it clear that Gabbert will have at least one more season to prove himself after declining to draft a quarterback or pursue one of the few caliber ones in costless agency. However, backup Chad Henne is still on the roster and will contend with Gabbert for the starting spot in training camp. After being rushed into the starting lineup in his rookie season, Gabbert ended up being benched and injured last year after failing to establish himself as an elite signal-caller. Gabbert will have to beat out Henne and show a vast improvement this year if he is to remain in the team’s plans for the future and avoid being labeled as yet another bust at QB for the Jaguars.

Josh Freeman, Tampa Bay Buccaneers.

In statistical terms, Josh Freeman had the best season of his career last year. However, after steering the Bucs on course for a playoff appearance in the beginning of the year, Freeman fell apart in the second half of the season, leaving both the team and its fans rueing what could have been.

The fact that Freeman is yet to receive a contract extension indicates that the Bucs are not totally sold on Freeman. Although he is a threat both running and passing the ball, head coach Greg Schiano does not view Freeman as a true leader on the field. Schiano has made it clear he will not hesitate to bring someone else in to create competition, no matter the position. With the moves made this offseason to improve the roster, the Buccaneers are expecting nothing but positive results. Freeman must prove himself this season as a true franchise quarterback, or his long-term future in Tampa will be in doubt.

Matt Schaub, Houston Texans.

Matt Schaub has established himself as an elite NFL quarterback since he arrived in Houston, leading the franchise to its first two AFC South division titles and consecutive playoff appearances. Down the stretch last season, however, Schaub began to struggle, and the Texans were again eliminated in the divisional round of the playoffs. By the time the 2013 season starts, Schaub will be 32, meaning his window of opportunity with this talented Texans team is slowly closing. There is no denying his talent and production in the regular season, but he’ll have to prove himself capable of winning in the playoffs this year. If he cannot come through, the Texans must begin their search for his eventual replacement.

Tom Brady, New England Patriots.

Yes, Tom Brady will enter the 2013 season with something to prove, specifically the fact that he still has the ability to take this team to the Super Bowl.

Things haven’t been the same for the Patriots since their loss against the New York Giants in Super Bowl XLII. The have failed to win a championship since their 2004 victory against the Eagles, and have recorded seven playoff loses in their last eight seasons.

Brady continues to play great football and remains among the best passers in the league, but will be 36 at the start of the new season and could be closer to retiring considering the punishment he has faced over the last few seasons. Brady has been sacked a total of 93 times in the last three years.

Brady’s talent is unquestioned, but he must prove he is still capable of taking this team to the promised land. The mounting pressure to win another Super Bowl, with yet another supporting cast of teammates on offense, continues to pile on both Brady and Belichick, who now appear close to the the end of their stellar NFL careers.