The Selecao skipper said there is no way the challenge which left the 22-year-old with a broken back was accidental and backed Dante to shine in his absence against Germany
Zuniga caught Neymar on the back with his knees in a reckless challenge which left the 22-year-old in agony, claiming he was unable to feel his legs, and ended his participation in the tournament.
The Colombia defender has since apologized and claimed the action was accidental, but Silva says his hypothesis is impossible.
"It's FIFA's decision [not to punish Zuniga] and we have to respect it," he said at his side's pre-match press conference ahead of the World Cup semifinal against Germany on Tuesday. "But I'm a central defender and I have never gone in with my knee high up like that on a rival's back.
"It was a cowardly tackle. There's no way you have you knee high up like that unless you want to cause a certain situation. It's not a normal match situation. That's my opinion on the matter."
Thiago Silva is suspended for Tuesday's game and let it slip that he'll be replaced by Bayern Munich defender Dante, causing coach Luiz Felipe Scolari to smile after the Brazil boss had repeatedly refused to reveal his starting lineup.
"Dante can replace me," the Paris Saint-Germain player said. "I spoke to him at the end of the Colombia match and I told him that his opportunity would come. Now it's up to the coach to select him.
"He is always one of the last left in the gym and one of the last to leave training. I played with him at Juventude in 2004 and I know how hard he was worked to get here, so I am sure he will be happy to go out now and show his skills."