According to El correo digital, Athletic Bilbao have agreed to pay €1 million to Real Sociedad for Xabi Castillo, with the possibility of a €600,000 increase depending on the player's performances.
Xabi Castillo came through Real Sociedad's youth ranks and emerged as a key member of the second division club.
The 23-year-old has now become Athletic's third summer signing, following in the footsteps of Diaz de Cerio and Oscar de Marcos.
Athletic coach, Inigo Diaz, revealed this morning that he wanted to sign three more players to complete the squad, and he seems to have landed his first target. The other two are believed to be Osasuna centre-back Miguel Flano and a striker.
Luís Mira, Goal.com