Athletic Bilbao’s Carlos Gurpegui has been banned from football for two years by the Spanish Football Federation.
The club announced that they would appeal against the ban that was imposed after the midfield player tested positive for the banned substance nandrolone following the opening game of the season against Real Sociedad on 1 September.
Athletic claimed the player’s body had produced the substance naturally but the disciplinary committee rejected the suggestion.
A statement on the club’s website, described the decision as an “absolute injustice”.
Athletic director Andoni Zubizarreta said: “This is totally unfair. The committee hasn’t shown any more proof apart from the first test and I think this kindof ban requires more tests to prove the player was guilty.”