For the second day in a row Tuesday, Morales made no mention of his trip to Cuba during public events in Bolivia.
Yet more questions surround Chavez’s political future, with the surgery coming two months after he won re-election to a six-year term.
If he is unable to continue in office, the Venezuelan Constitution calls for new elections to be held. Chavez has asked his followers to back Maduro, his hand-picked successor, in that event.
Venezuelan officials have said Chavez might not return in time for his Jan. 10 inauguration.
Opposition leaders have argued that the constitution does not allow the president’s swearing-in to be postponed, and say new elections should be called if Chavez is unable to take the oath on time.
But government officials have said the constitution lets the Supreme Court administer the oath of office at any time if the National Assembly is unable to do it Jan. 10 as scheduled.
Associated Press writers Peter Orsi in Havana, Vivian Sequera in Caracas, Camilo Hernandez in Bogota, Colombia, and Paola Flores in La Paz, Bolivia, contributed to this report.