Spain Under 21 international Unai Nuñez has signed a new deal at Athletic Club Bilbao following recent reports linking him with a move to Barcelona.

The 20-year defender only made his first-team debut at San Mames earlier in August after being promoted by his former manager at the second team Cuco Ziganda.

Nuñez has since became an unmovable presence in Athletic's defence, starting the opening 10 games of La Liga and also being rewarded with a regular place in the Spanish Under 21 national team.

Earlier this month Sport reported that the Spaniard's meteoric development had also attracted the attention of Barcelona with manager Ernesto Valverde being on the hunt for two new centre-backs ahead of next season.

The Barcelona boss currently has Gerard Pique and Samuel Umtiti to cover the position but 33-year-old Javier Mascherano and 31-year-old Thomas Vermaelen have suggested in recent days that they could leave the Nou Camp in the near future after being grown frustrated with their lack of playing time.

The Catalans are tipped to activate a first refusal to sign Yerry Mina from Palmeiras either in January or in the summer but they would still need an extra man if both Mascherano and Vermaelen leave.

Sport said that Nuñez was one of the players under consideration with Barcelona having already made an initial approach to his camp to sound out whether he will consider a future move to the Nou Camp.

However, it looks like Barcelona will have to look somewhere else to find a new defender after Nuñez has committed his long-term future to San Mames by signing a new deal until 2023.

Furthermore, Athletic have agreed to increase his release clause to €30m (£26.4m, $30.9) in order to ward off Barcelona and other potential suitors.

"Athletic Club and Unai Nuñez have signed the renewal contract by which the player will remain in the rojiblanca discipline until 30 June 2023. His cancellation clause will be 30 million Euros," the Basque side confirmed through an official statement.