Shin also handed a first senior call-up to exciting young winger Lee Seung-woo, who was regarded as one of Barcelona's most promising talents at its La Masia youth academy before he made the switch to Italy's Hellas Verona last year.
The maiden selections of 20-year-old Lee, Jeju defender Oh Ban-suk and Incheon midfielder Moon Seon-min came as something of a surprise but Shin said they were not there just to make up the numbers.
"Even though there's not a lot of time left until the World Cup, they could make it if they impress," Shin told reporters.
Shin said he had seen exactly what Lee could bring to the table after coaching the South Korea squad at the Under-20 World Cup last year.
Lee was one of the standouts of the tournament, scoring twice, including against Argentina in a 2-1 victory, as hosts South Korea reached the last 16.
"I am more aware of his strong points and weaknesses than anyone else after going through the Under-20 World Cup together," Shin added.
Shin, 49, said he had planned to forgo a preliminary squad and name just 23 players but injuries had forced him to shuffle his pack. He said his main selection issues were in defence.
The squad is split evenly between domestic and foreign-based players, and Shin will have to submit his final squad by June 4.
The Koreans, who will face Mexico, Sweden and defending champions Germany in their group at the finals, are making their ninth straight appearance at the World Cup.
The are scheduled to play tune-up matches against Honduras, Bosnia, Bolivia and Senegal before meeting Sweden in their opening Group F encounter in Nizhny Novgorod on June 18.
(Reporting by Joori Roh; Writing by Peter Rutherford; Editing by John O'Brien)
