Real Sociedad expect Willian Jose to sign permanently with Wolves.
The centre-forward moved to Wolves last week on-loan to the end of this season with an option to sign permanently for €17.5m.
Mundo Deportivo says La Real management are convinced Willian will remain in England long-term.
Indeed, should Wolves choose to send the Brazilian back to San Sebastian, they will be forced to cough up a €3m penalty.
Real Sociedad have already signed a replacement for Willian in Carlos Fernandez, who joined from Sevilla last week.

