Athletic Bilbao midfielder Ander Herrera is set to be sidelined for up to six weeks after undergoing an operation on a sports hernia.
The 23-year-old, who was this summer part of Spain's Olympic squad, successfully went under the knife on Friday morning in Munich.
Herrera had been ruled out of last weekend's Primera Division win over Real Valladolid with the problem.
A statement on Athletic's official website read: "If there are no complications in the post-op period, the player will be discharged on Saturday, 8th September and will return to his home.
"The recovery period for this type of operation is between four and six weeks."