The 37-year-old, who was capped twice by Spain, won the Copa del Rey with Athletic earlier in April, his first major trophy with the club after arriving from Atletico Madrid in 2015.
Real Madrid suffered a shock defeat in the Spanish Super Cup on Thursday as Athletic Bilbao pulled off a 2-1 victory in Malaga to reach Sunday's final against Barcelona.
Real Madrid suffered a shock defeat in the Spanish Super Cup on Thursday as Athletic Bilbao pulled off a 2-1 victory in Malaga to reach Sunday's final against Barcelona.