ATHENS — Prime Minister Antonis Samaras appointed Yannis Stournaras, an economist and former government adviser who served as development minister in the previous caretaker administration, as the country’s new finance minister Tuesday.

The appointment came a day after the man originally designated to assume the post, Vassilis Rapanos, chairman of the National Bank of Greece, resigned before he could be sworn in, citing health problems. Rapanos, who has a history of health ailments and was admitted to a hospital with nausea and stomach pains Friday, was released Tuesday.

Stournaras, 55, is the founder of the Foundation for Economic and Industrial Research. He has advised previous Socialist governments. Formerly an adviser to the Finance Ministry and the country’s central bank, Stournaras is an economics professor at Athens University.

Speaking at a book presentation earlier in the day, Stournaras said he was optimistic about his new job.

‘‘I think there are possibilities for Greece to emerge from the crisis,’’ he said. ‘‘Greece has enormous potential, but we must pass through a wall of established ways of thinking if Greece is to change.’’

The new finance minister, who must be sworn in, will not travel to a coming EU leaders’ summit meeting, where his predecessor, George Zannias, the caretaker finance minister, will represent Greece as part of a delegation led by President Karolos Papoulias, a spokesman for the prime minister said. The president is standing in for Samaras, who has been advised against traveling after an operation for a detached retina.