K League
In 1994, Yoo joined a K League club Ulsan Hyundai Horang-i, and was selected as a defender of the K League Best XI right after his first season. In 1996, he won the 1996 K League with Ulsan. In 1998, he won the K League scoring title, scoring 14 goals in 20 games, and was named as a midfielder in the K League Best XI.