"If any association withdraws or is excluded from the competition, the FIFA Organising Committee shall decide on the matter at its sole discretion and take whatever action is deemed necessary," read the Fifa regulations.
"The FIFA Organising Committee may in particular decide to replace the association in question with another association."
If Fifa went on rankings then Chile would get the nod, currently ranked 10th in the latest World rankings. Chile finished sixth in South American qualifying, behind Peru on goal difference.
Italy, ranked 14th in the latest, were knocked out in the UEFA qualifying playoffs by Sweden, however Fifa regulations state only 13 European teams can play at a World Cup.
USA could also be in the mix if it was a financial decision by Fifa. The All Whites could claim they would be the fairest decision since they were knocked out by Peru.