The tournament is due to take place in South Africa - the first World Cup to be staged in Africa - but rising concerns over continued security problems in the area have put the possibility of the country hosting football's most prestigious competition into doubt.
However, while Blatter admits that there is an alternative in place, he remains confident the World Cup will go ahead as planned.
"I would be a very negligent president if I hadn't put away in a drawer somewhere a plan B," said Blatter.
"However, only a natural catastrophe would change things.
"If we had to activate the plan B, we would take our decision after the Confederations Cup."
Next year's Confederation Cup is set to be held in South Africa and will act as a dry run for the World Cup a year later.