Pary arrived from neighboring Argentina,where Morales and several of his senior officials have stayed in the past weeks since early November to seek political asylum.
In an interview with local radio station in central Cochabamba, Pary said Bolivians wanted him to return to throw his hat in the ring as a potential candidate.
"I will be where the social movements decide I should be," said Pary.
Bolivia has been plunged into political uncertainty since the opposition rejected the re-election of the country's first indigenous president, Morales, to a fourth term in October elections, citing electoral fraud.
Morales resigned and fled to Mexico after Bolivia's military and police forces sided with the opposition and withdrew their support for his leadership. He later went to Argentina.
Opposition lawmaker Jeanine Anez took over as interim president and presided over the process to hold new elections, with the participation of the Legislative Assembly, where Morales' Movement Towards Socialism party holds a majority of seats.
Elections are to be held on May 3 to elect lawmakers as well as a new president and vice president, according to the Supreme Electoral Court.