Sources in Spain have stated that an agreement between Sordo and Ford has already been reached.
Sordo's deal to drive a factory Fiesta RS WRC is anticipated to be for the South American event only, with regular driver Latvala expected to be fit again for the following round in Greece.
Latvala was ruled out of Rally Argentina after he broke his collarbone in a skiing accident last week.
Sordo is currently contracted to drive a Mini John Cooper Works WRC for the Prodrive WRC Team, but sources confirm he has been permitted to drive for the rival squad. Prodrive is not contesting every round this year following the end of its factory relationship with Mini.
Ford World Rally Team senior management yesterday confirmed Sordo was on a shortlist of possible replacements for the Finn, but denied any deal had been done.
Sordo was unavailable for comment, but has re-tweeted a website story confirming his deal with Ford.