1 9 8 8 ) ▁is ▁a ▁Spanish ▁professional ▁footballer ▁who ▁plays ▁for ▁Athlet ic ▁Bil ba o ▁as ▁a ▁left ▁back . ▁ ▁Club ▁career ▁Born ▁in ▁Z umar rag a , ▁G ip uz ko a , ▁Bal en zi aga ▁started ▁his ▁football ▁gro oming ▁at ▁Real ▁Soci edad , ▁playing ▁two ▁full ▁seasons ▁with ▁its ▁B - team ▁in ▁the ▁third ▁division . ▁However , ▁in ▁ 2 0 0 8 – 0 9 , ▁he ▁switched ▁to ▁neighb ours ▁Athlet ic ▁Bil ba o . ▁ ▁Initial ly ▁thought ▁of ▁as ▁a ▁member ▁of ▁the ▁reserve ▁side , ▁Bal en zi aga ▁quickly ▁beat ▁competition ▁from ▁veter ans ▁Ko ik ili ▁and ▁J avier ▁Cas as ▁to ▁become ▁the ▁und is put ed ▁first - choice ▁for ▁the ▁vast ▁majority ▁of ▁the ▁campaign , ▁making ▁his ▁first - team ▁debut ▁on ▁ 1 4 ▁September ▁ 2 0 0 8 ▁in ▁a ▁ 0 – 0 ▁away ▁draw ▁against ▁M ál aga ▁CF ▁– ▁another ▁club ▁gradu ate , ▁And er ▁It urr as pe , ▁also ▁made ▁his ▁first ▁La ▁Liga ▁appearance ▁in ▁that ▁game . ▁ ▁In ▁July ▁ 2 0 0 9 , ▁Athlet ic ▁bought ▁X ab ier ▁Cast illo ▁from ▁neighb ours ▁Real ▁Soci edad ▁and ▁Bal en zi aga , ▁seeing ▁his ▁ch ances ▁for ▁the ▁up coming ▁season ▁dim , ▁accepted ▁a ▁loan ▁move ▁to ▁CD ▁N uman cia , ▁fresh ly ▁re leg ated ▁from ▁the ▁top ▁division . ▁He