Aritz progressed through the ranks of Athletic Bilbao's youth system before making his debut for them against FC Barcelona in 2002. However, his real rise to prominence came when he left Bilbao to play for Burgos FC and Real Valladolid in the Segunda Division where after 80 games his goal scoring ratio was almost 2:1. A return to Bilbao soon beckonened with the club paying €3 million for his services once again.

Aritz, a striker with excellent ball control, strength, speed and importantly, a high work rate, fitted back into the Bilbao set-up with ease. His forward and direct play went on to impresse managers and scouts across La Liga and in the summer of 2008, RCD Mallorca purchard Aritz for €6 million.

At Mallorca, Aritz made an immediate impact ending his first season as their top goalscorer. In his second season, Aritz improved his goalscoring tally and helped his team qualify, through league position, to the Europa League.

In July 2010, Aritz was seen as an ideal replacement for David Villa at Valencia CF and has since completed a €4 million to the club.

Aritz possesses unique capabilities as a superbly built, goal-scoring striker who excels in one-on-one situations against defenders and in retaining possession.