Athletic Bilbao have confirmed that that will stand by Carlos Gurpegi after it was revealed he tested positive for nandrolone.

The 22-year-old midfielder failed the test taken after the 4-2 defeat to Real Sociedad on the opening day of the season. The club are still awaiting the results of a second test..

A statement from Bilbao said: “Athletic want to make it clear that the player has not taken that product or anything similar, nor has anything like that been given to him by the club’s medical services.

“Therefore we want to express our utmost confidence in the player’s behaviour and we will put all of our judicial and technical services at his disposition with the aim of discovering the origin of the mentioned substance.”