National soccer striker Lee Dong-gook left Wednesday for Germany for treatment of his injured right knee.

The Pohang Steelers star will decide by Friday whether to have surgery or rehabilitation based on medical results in Seoul and analysis by the German rehabilitation center Sporeg.

His knee will be checked as soon he arrives in Germany.

Lee was left off the national squad in the 2002 World Cup, and is likely not to choose surgery for a chance to play in this year's World Cup.