Barcelona have received a major update over their potential pursuit of Jonathan Tah, with reports in Germany claiming that the centre-back has a €25m (£22.3m, $29.1m) release clause in his contract at Bayer Leverkusen.

Sport Bild has revealed the news after pointing out that the presence of scouts from the La Liga giants at the BayArena has become a regular occurence in the opening part of the season.

Tah joined Leverkusen from Hamburg in the summer of 2015 after garnering a big reputation during a loan spell with Fortuna Dusseldorf.

Sport Bild says Leverkusen paid around €8m to secure his services but agreed to include a €25m buy-out clause in his contract ahead of a potential sale to another club.

The Bundesliga side will thus be unable to prevent his departure if any club meet that clause, but Barcelona or any other potential suitors will still need to decide whether it is worth making such aninvestment in the 21-year-old defender.

Previous reports in Spain had already claimed that Barcelona technical secretary Robert Fernandez has been in attendance in several games for Leverkusen this season to keep a close eye on the defender's development ahead of making a potential move to lure him to the Nou Camp.

However, the La Liga leaders have also been linked with other defenders likes RB Leipzig starlet Dayout Upamecano and Ajax youngster Matthijs de Ligt as they are said to to be on the hunt for two new centre-backs to bolster Ernesto Valverde's back-line.

The Barcelona boss currently has four optiond at his disposal to cover the heart of the defence in the form of Gerard Pique, Samuel Umtiti, Javier Mascherano and Thomas Vermaelen. However, the last two are already in the wrong side of 30 and have suggested in recent week that their days at Barcelona could be numbered due to their lack of playing time.

The La Liga giants have been tipped to sign Colombian international Yerry Mina with the club having a first refusal to seal the 23-year-old centre-back from Palmeiras in a deal worth around €9m.

However, they will need another centre-back like Tah if both Mascherano and Vermaelen decide to leave the Nou Camp.

One way or another such moves might not happen until the summer after earlier this week Valverde suggested that Barcelona won't sign a new centre-back in January unless any of his current players depart.

"I think that with four centre-backs in the squad is enough. Right now we have four and Vermaelen is yet to play in La Liga. We have four players for two positions," Valverde said in a press conference ahead of the Champions League clash with Olympiacos.

"Another thing would be if one of them is not here [because someone leaves in January] but in principle we have four centre-backs and we think that we can pull forward with them [until the end of the campaign]."