The Bayern Munich defender has returned to the Catalan club's radar, with Hansi Flick's side understood to be looking for an experienced centre-back who could provide additional stability alongside Pau Cubarsí.
According to Sky Deutschland, Barcelona have already made an enquiry about the 30-year-old's situation, exploring whether a move could be possible during the winter market.
Tah is an established Germany international and was previously considered by Barcelona before joining Bayern Munich. His experience and physical presence make him an attractive option for a club looking to reinforce its defensive options without relying entirely on younger players.
Deco is understood to be prioritising the addition of an experienced defender, with Barcelona keen to improve the depth and leadership available in the centre of their back line.
Tah fits that profile, but the initial indications from Germany suggest that a deal would be extremely difficult to complete.
Bayern are not considering allowing the defender to leave in January. He remains under contract at the Allianz Arena until the summer of 2029, and the German champions regard him as an important part of their plans.
The player is also understood to be happy in Munich and has no current intention of seeking a transfer.
That leaves Barcelona facing resistance from both the club and the player, despite having made an approach to establish his availability.
Tah only joined Bayern in the summer of 2025 after leaving Bayer Leverkusen, where he had established himself as one of the Bundesliga's most reliable central defenders.
His move to Munich represented a significant step in his career, and Bayern secured his services with a long-term contract running until 2029.
Barcelona's interest is not entirely new. The Catalan club had previously explored the possibility of signing Tah before his move to Bayern, but the German side ultimately won the race for his signature.
The defender's current situation has nevertheless brought his name back into discussions at the Camp Nou. Although he has not been an automatic starter in every match this season, Bayern remain reluctant to weaken their defensive options midway through the campaign.
For Barcelona, the appeal is clear. Cubarsí has become a key figure despite his young age, but adding an experienced international defender would provide Flick with another established option and allow greater flexibility when managing the demands of domestic and European competition.
However, the immediate obstacles are considerable. Bayern have no desire to sell, Tah is settled in Munich and his contract gives the Bundesliga club a strong negotiating position.
The enquiry therefore appears to represent an initial exploration rather than evidence that a transfer is close.
Barcelona may continue monitoring the situation as the January window approaches, but unless Bayern change their stance or Tah reconsiders his position, the Catalan club are likely to have to look elsewhere for the defensive reinforcement Deco wants.