La Liga's new season is in full swing, and Barcelona is atop the tables with a five point lead on their rivals, Real Madrid.
Tito Vilanova's side has yet to even hit full stride, but they have still gotten the full three points from every match so far.
That success is representative of a team that is considered the best of this generation. It is not because of any one player, but because of an incredible team effort.
I recently looked at the five least expendable Real Madrid players under Jose Mourinho, and I have decided to follow that up by listing Barcelona's five players who are the most important to the team's success.
La Blaugrana work as a unit and well-run machine perhaps more than any other team in football. The failure of one core player to do his job affects the whole team.
Almost every single player is vital because of how interconnected the ability of one player is to the rest of the team.
So when I list these five players as the most important, that is not to say that no one else is important, nor is it saying that the gap between these players is great. In fact, the five players on this list are almost equal in value to the team.
With all that said, let's take a look at the five least most important players on Tito Vilanova's roster.
It speaks volumes that a 34-year-old center back who is no longer even able to play every match can be considered one of the five most important players for one of Europe's top teams.
Carles Puyol is just that important to Barcelona, though. Without the versatile leader on the pitch, Barcelona are simply a weaker team.
It is no coincidence that as the captain's fitness has declined, so has the strength of Barcelona's defense.
It is also notable that Barcelona's trophy count has gotten smaller each season that Puyol has gotten older and had to play less.
Gerard Pique and Javier Mascherano are both incredible central defenders, the former being world class already.
But neither is on the level that el Capitan has been throughout his career. Even now, at almost a decade older than Pique and about two years past his prime, Puyol is still the best defender on the pitch when he plays.
More importantly, neither player has the leadership quality of el Corazón de León. No one on the Spanish National Team has become that leader yet either.
Barça's legendary No. 5 is perhaps the greatest center back of his generation and the one who every Blaugrana defender will be measured against for many years to come.
Don Andres is the reigning UEFA Player of the Year and has won virtually every team trophy possible—yet he is not even close to being done.
For many, Iniesta has now overtaken his national and club teammate Xavi as the best midfielder in football. He is one of the best big-game players in the game and he is integral to Barcelona's success.
El Ilusionista has earned his name for the magic he produces with the ball as well as the seemingly impossible situations that he works his way out of in midfield.
If Barcelona played without names or numbers on their jerseys, Iniesta would stick out in midfield because he is the one who carries the ball forward to create space and chances for his teammates.
La Blaugrana are renowned for their ability to use quick, one-touch passing as a weapon that sends the opposition in circles, chasing the ball around hopelessly and using up their energy in the process.
Iniesta, on the other hand, has such great control that it appears as though the ball is afraid to leave his feet.
He is a master of luring players to pressure and often foul him. He attacks defenders with the ball and makes them think they have a chance to dispossess him.
Then, just as the other player thinks the ball is his, Iniesta either dances out of an immovable jam or passes the ball to a teammate in the space the magician created.
It is that confidence, vision, and unbelievable control of the ball that makes Andres Iniesta invaluable to his club.
It is hard to explain just how valuable Xavi has been to Barcelona, even now as he nears 33 years of age.
Without him at the club, it is safe to assume that La Blaugrana would not have had anywhere near the same success.
Without Xavi, Pep Guardiola would not have won six trophies in his first season, Messi would not have won so many Ballon d'Ors and Barcelona's system would not be as successful or praised as it currently is.
The team would also not have become one of the greatest club sides in the history of European football.
Xavi is the director and the orchestrator. He is the engine that makes Barça run. It is almost a crime that he has never won—and possibly will never win—a Ballon d'Or because of how biased voters are toward forwards.
The Spanish master is the best passer alive, and he is the standard for modern central midfielders to be measured by.
Some would argue that he has declined in the past season, but any loss of speed or fitness has not lessened his influence on the pitch.
Without Xavi, Barcelona is slower, less creative, and less unstoppable in possession. The entire complexion of the team changes without their visionary on the pitch.
If anything keeps Cules up at night, it is the thought of their team lining up without their greatest ever midfielder leading their team into battle.
Xavi Hernandez is a once in a generation type player who will never be replaced for club and country.
Busquets was the second-most important player for Barcelona last term, and he is as valuable as Xavi or Iniesta to the success of his team.
Busi is the reason Barcelona's midfielders get so much time and space on the ball and the reason his defenders are allowed so much freedom to roam.
It is because of Sergio that Xavi and Iniesta can play with such confidence, knowing they are covered by one of the absolute best holders in the world.
Barça's No. 16 is not a strong, traditional bruiser in midfield, but he is a player who excels at cleaning up mistakes and cutting off the opposition's attack.
His positional awareness is as good as any defensive midfielder in football and his passing is the best at his position.
Barcelona's defense has gotten progressively less reliable over the last three seasons, but many still fail to realize just how poor the back line plays at times.
Why is that? Because Busi makes them look better than they are, just as he and Xabi Alonso do for the Spanish national team.
Most of his greatness goes unnoticed to casual fans, but players and coaches alike are more than aware of his incredible talents.
He never gets the credit he deserves and often gets ignored when discussing the best midfielders on the planet, but Sergio Busquets is completely irreplaceable for club and country.
Some say he is the second best player in the world, most say he just edges Cristiano Ronaldo for that honor.
Regardless of who is better, Lionel Messi is more important to the success of his team.
Evidence of this can be seen by the sheer number of goals he scores every season and, more importantly, the large percentage of total team goals he puts back every year.
Without Messi, Barcelona would still have a world class team. The midfield would still be the best in football and the defense is still full of great talents.
However, none of that beautiful football or countless created chances matter if no one is there to put the ball in the back of the net.
La Pulga Atomico scores over half of Barça's goals, creates countless more, and is the driver of the entire offense. No one else in football is so instrumental in creating and scoring goals for his team.
Last season, Barcelona proved to be too reliant on Messi and it already looks like more of the same this season.
Fans hope that will change when David Villa and Pedro get back to full strength, but that is not a certainty.
At the moment, that makes Messi the most important player on the team, but Barça's No. 10 should find some aid from his teammates soon. Fans certainly hope so at least.
As the rest of Barça's forwards get healthy and begin taking some of the scoring load off of their best player, it could allow the Argentinian to fall a couple spots down on this list.
Until then, the most irreplaceable player on Tito Vilanova's Barcelona is Lionel Messi.