Sun gathered his 24-man team for the Jakarta-Palembang Asian Games on Saturday, with the first practice scheduled for later in the day at Jamsil Stadium in Seoul. The team is made up entirely of players from the Korea Baseball Organization, the top domestic league.
Japan will not send its Nippon Professional Baseball (NPB) stars, having instead put together a team of amateurs.
On paper, South Korea should have the most talented team. But Sun said anything can happen in baseball.
"We'll not let our guard down, because there are so many variables in baseball," Sun said at a press conference. "Chinese Taipei will be without some pitchers, but they still have a lot of firepower. Japan will have some talented young pitchers."
Sun first announced his roster on June 11 but made four changes last week to replace injured and slumping players.
But one controversial player didn't get the axe. LG Twins shortstop Oh Ji-hwan remains on the team despite leading the KBO with 120 strikeouts and 17 errors.
Critics believe Sun named Oh and has kept him on the team to help him earn an exemption from mandatory military service. Male athletes who win Asian Games gold medals won't have to serve in the armed forces for two years like other healthy South Korean men, and Sun has faced heat for picking undeserving players based on their military status.
Since his national team selection in June, Oh's batting average dropped from .300 to .277. He has had a penchant for botching routine plays on the field.
Sun defended his choice, saying, "I believe we had the best team we could possibly have in June, and we can say the same thing about the team we have today."
On the controversy surrounding Oh, the manager said, "I think he must be quite stressed out about the situation, but winning gold will take care of things."
South Korea will train at Jamsil Stadium until next Wednesday and head to Jakarta the following day. South Korea will start its "three-peat" bid on Aug. 26.
It's in Group A with Chinese Taipei, Indonesia and Hong Kong. (Yonhap)