Borussia Dortmund striker Alexander Frei will not play again in 2007 after being sent for a calf operation.
Frei has not played for Dortmund this season due to the calf problem which was the result of a hip operation in May.
He will now undergo surgery on his current injury next Tuesday and Dortmund are not expecting the Switzerland international to return until after the winter break.
"After speaking to doctors in Switzerland and Germany, Alexander Frei decided to have an operation to cure his calf muscle problems," read a club statement.
"These problems in his right leg are a result of the operation on his hip in May."
Dortmund coach Thomas Doll admits a decision on a possible comeback date will be made after Frei's operation.
Doll said: "We'll talk about all that once the operation has been concluded."