The 30-year-old is expected to leave Fulham in the January transfer window after being transfer listed by the club.
But Seol turned down an offer to join South China for the rest of the season.
“It was a bit disappointing as we were close to signing a classy player,” South China chairman Steven Lo told the South China Morning Post.
“But his decision is understandable as Seol wants to boost his chances of playing for his country in the World Cup finals. Playing in the Hong Kong league would not do him any favours.”
