"I had a stomach virus that has not allowed me to train this morning (Thursday) and I have had to put back everything," the World No 1 said on his website.
"We are three days from the start of the tournament and without having been able to train a single day since Australia it means it has been impossible for me to prepare sufficiently to compete in an event so important as Buenos Aires."
Nadal's back injury contributed to his surprise four-set defeat by Switzerland's number eight seed Stanislas Wawrinka in the Australian Open final at the end of January.
Image: Rafael Nadal
Photograph: Eliseo Fernandez/Reuters
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