Yoon hurled one - run baseball over 7.1 innings and fanned 10 batters against reigning national champion Kyungsung University in his first 2009 season game as a starter .
As a sophomore at Korea University in 2009 Yoon was promoted to the team 's starting rotation .
Yoon hurled one - run baseball over 7.1 innings and fanned 10 batters against reigning national champion Kyungsung University in Yoon 's first 2009 season game as a starter .
As a sophomore at Korea University in 2009 Yoon was promoted to the team 's starting rotation .