"In my opinion it was a cowardly tackle," the Paris Saint-Germain defender said on the eve of his side's World Cup semi-final against Germany today.
"I am a defender, I know how to mark a player and there is no way you can get the ball by putting a knee in the back.
"It is not something that comes about in a normal match situation."
FIFA turned down a request from the Brazilian Football Confederation (CBF) to ban Zuniga on Monday because the incident had been seen by the match officials at the time and no action was taken.
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The 29-year-old was booked 25 minutes from time with Brazil leading 1-0 through his early strike for impeding Colombian goalkeeper David Ospina.
"In no moment did I intend to take the ball from the goalkeeper. I was trying so hard not to commit any fouls, the only foul I remember was the yellow card and it is very difficult to miss the game," he added.
"But I really trust the players on the pitch. No matter the 11 players we will be well represented.