Athletic did not mention City or any other club in a statement on their website, but did confirm that Laporte's release clause had been met and thanked the player for his contributions.

Laporte also issued a farewell statement on Athletic's official Twitter account.

The club's statement read: "Today, 29th January 2018, the Liga Profesional de Futbol (LPF) has certified to Athletic Club that the player Aymeric Laporte has met the requirements demanded in the applicable legislation for the valid unilateral resolution of the employment contract that bound him to our club.

"Said certification indicates that the player has unilaterally shown his will to terminate the contractual relationship that bound him since 2009-2010 season and that the amount of compensation established in the contract has been deposited.

"Athletic Club would like to thank the player for his dedication during the time he has been with the club."

Laporte was left out of Athletic's matchday squad to face Eibar at San Mames on Friday night amid speculation of a possible big-money switch to City.

The former France Under-21 international had been a virtual ever-present for Athletic this season but, after being named in Jose Angel Ziganda's 20-man squad for the LaLiga clash the previous day, he was not selected for the Basque derby.

Laporte, who came up through the youth ranks at Athletic after joining the Lions in 2010, said he was leaving the Basque outfit for a "new challenge" but that would never forget the club.

His farewell message, written in both Spanish and English, read: "To all the Athletic family. So much to tell in few lines. I want to thank you for everything you have given me.

"I arrived as a teenager and here I grew up as a person and as a footballer. My farewell, ahead of a new challenge in my professional career, I don't want it be a goodbye, but a see you soon.

"Here I leave a unique club, different and I will never forget you."