The 27-year-old forward failed in a short spell with Werder Bremen five years ago but he has since matured into a top striker for his club Pohang Steelers and South Korea.
It is strongly believed that Zoltan Gera will make the move to the Riverisde this week with Brad Jones moving to the Hawthorns in a cash plus player exchange.
Fabio Rochemback has been told to stay and fight for his place at the Riverside by manager Gareth Southgate, however the Boro boss also said that he is unlikely to feature for the first team during the transfer window because it is too much of a distraction for the Brazilian.
Boro have also issued a ‘hands-off' warning to would be suitors of Mark Viduka and Stewart Downing, as a number of clubs have shown interest in the pair.