Brazil has not lost at home since 1975 and has won the World Cup five times. Colombia failed to qualify for the last three World Cups and has never even reached the group of eight before this year.

So on paper, it seems that the Brazilians have momentum, experience and history on their side, and that the underdog Colombians have much to overcome if they hope to beat the Brazilians in their home country.

But the Colombians have the 2014 tournament's breakout star scorer, James Rodriguez, who already has a stunning five goals and two assists. And though Brazil has bona fide superstars like Neymar, it is missing one of its key players for Friday's match.

The man sitting out the massively important match against Colombia is Luiz Gustavo, not exactly a household name for casual fans, but easily one of the most important pieces of Brazil's squad.

Gustavo, a defensive-minded midfielder, doesn't garner as many headlines as scoring machines like Rodriguez and Neymar, but the role he plays for Brazil is one that cannot be overstated.

Considered by many to be one of the Brazil's best tacklers, he is also one of their key playmakers, executing passes to strikers and stealing the ball from opponents with panache and skill. His soccer knowledge is seen as excellent, and he reads the game well, effectively spacing the pitch and helping to set up offensive plays.

Though the Wolfsburg man has only had one assist and zero goals so far in the tournament and is perceived as too slow to be considered as highly as he often is, he will be a difficult player to replace.

Paulinho and Fernardinho will be looked to to fill his big shoes, but the Brazilians will need to pick up their play if they hope to make up for Gustavo's absence.

Gustavo has run with the ball for a stunning 16.3 km (10.1 miles) in four matches, outpacing teammate Neymar, and he has recovered the soccer ball 34 times, according to the Guardian.

He was suspended for one game after being hit with a yellow card during Tuesday's match against Chile.

“A guy in my position on the pitch cannot think twice. Unfortunately I fouled an opponent and got the second booking but I am proud to have helped the team,” Gustavo said.

Just how important Gustavo is to the Brazilians will be revealed Friday afternoon as the teams face off in Brazil.