Barcelona have drawn up a list of targets to strengthen their defence and could sign a centre-back in January.
With Thomas Vermaelen out of favour and constantly plagued by injuries and Javier Mascherano approaching the end of his Camp Nou career, the Blaugrana are eager to reshape their defence over the next two transfer windows.
The Catalan club have tied up an agreement with Palmeiras for Colombian international Yerry Mina for a fee in the region of €9 million, with that deal set to be completed in the summer.
However, coach Ernesto Valverde is also keen on bringing in a player with experience in European football after Barca opted against paying €32m for Real Sociedad's Inigo Martinez in the summer.
Barca have long tracked another Colombian, Davinson Sanchez, but bringing in the South American defender now looks impossible after he moved from Ajax to Tottenham in the summer for a fee of €46m and signed a six-year contract at the north London club.
The Catalans look set to move instead for another Ajax talent, Matthijs de Ligt. The 18-year-old would be significantly cheaper, around €20m, and is already earning a reputation as one of the exciting young centre-backs in Europe. The Dutch defender is now Barca's top target and could arrive in January.
Also under consideration is RB Leipzig's young French defender Dayot Upamecano, who is 19 years of age and has represented his country at youth level. The teenager has been linked with a move to Liverpool as well.
Ideally, Valverde would like to bring in a more experienced player and options include Napoli's Senegal international Kalidou Koulibaly and Lazio's Dutch defender Stefan de Vrij.
Both of those two players are likely to be expensive, though, and Barca could well be deterred by fees in the region of €50m for players who, in theory, would not be automatic starters for the Catalan club, with Gerard Pique and Samuel Umtiti very much in favour at Camp Nou.
Another top-class centre-back would give Valverde the chance to play 3-5-2 at times, a formation he used in the Spanish Supercopa second leg against Real Madrid, but with the Catalans still keen on signing Philippe Coutinho in the summer, they look likely to opt for a younger and cheaper option at this point.
That makes De Ligt the current favourite to strengthen the Barca back line, along with Mina in the summer, while Brazilian defender Marlon will also return from his loan at Nice in July to provide another alternative for the 2018-19 season.