The 22-year-old was suspended for drugs use by the Spanish Football Federation for the second time on Thursday, after he appealed against the original decision from earlier this year.
However, the committee for sporting discipline has decided Gurpegi is not guilty of taking Nandrolone - which he tested positive for after the opening game of the season against Real Sociedad.
Gurpegi is now eligible to play in Bilbao's game against Deportivo La Coruna on Sunday.
The University of Extremadura did tests on Gurpegi and revealed that he naturally produced a larger than normal amount of Nandrolone and it seems the sporting discipline panel took the evidence very seriously.
