Aranzubia, a product of Athletic's youth system, has added four years to his existing contract following negotiations at the weekend. He can boost his salary on the basis of matches played but no wage increase was included in the deal.
The 24-year-old is thought to be in Spain coach Iñaki Sáez's plans. Clearly delighted with the way the season has gone, Aranzubia told uefa.com: "
It has been a great year both for me and for the club. We are fighting for a place in the UEFA Cup and it would be fantastic to end the season on a high."
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