Barcelona's defensive rebuild has a domino problem. ONE reports that the club's pursuit of RB Leipzig centre-back Castello Lukeba is not a straightforward pursuit at all, but a plan that only gets moving once one of Jules Kounde or Alejandro Balde walks out the door.

Hansi Flick is said to rate the 23-year-old Frenchman for his speed, his left foot and his aggression out of the back — attributes the German coach has publicly prized since he arrived at Camp Nou. But Lukeba does not come cheap, and Barcelona's finances mean any incoming fee has to be funded by an outgoing sale first.

That is where Kounde and Balde come in. According to ONE, Flick has left the door open for either defender to leave this summer, and the club would accelerate talks for Lukeba the moment one of them departs.

The irony is that Kounde only just committed his long-term future to the club. Barcelona confirmed in August that the France international had signed a new contract running to 2030, ending speculation over interest from the Premier League after he reportedly turned down an approach to stay put, according to football-espana.net and ESPN.

A new deal, though, has not made him untouchable. Spanish outlets covering the club, including Sport1-Maariv, have described Barcelona's hierarchy as viewing Kounde as a sellable asset if the right offer lands — a reminder that in Barcelona's current financial reality, a long contract can raise a player's price rather than guarantee his place.

Balde's situation looks further along. Multiple outlets, including Forbes and Barca Blaugranes, reported this weekend that the 22-year-old left-back has decided he wants out after growing frustrated with his standing under Flick, with agent Jorge Mendes said to be working the phones to find him a new home before the window closes.

Manchester United have been the club most consistently linked with Balde, having already opened dialogue with his camp as they search for a long-term left-back. Fabrizio Romano has offered a note of caution, however, stating that Balde is not actively pushing for an exit and that any decision remains in the club's hands rather than the player's.

Gerard Martin is currently Barcelona's only recognised natural left-back should Balde leave, which underlines why the club would need Lukeba — even if he is naturally a centre-back — to help solve more than one problem at once, either sliding into central defence or covering across the back line as Flick's squad is reshuffled.

Lukeba himself has been strongly linked with a Bundesliga exit after three seasons in Leipzig, with a release clause reported in the region of 80 million euros, though Leipzig are believed willing to negotiate down from that figure. Arsenal and Manchester United have also been credited with interest in the France Under-21 international turned senior squad member.

For now, ONE frames this as contingent rather than close: no fee for Lukeba has been agreed, and no exit for Kounde or Balde has been finalised. But with the transfer window entering its final stretch, Barcelona's sporting director Deco and Flick appear to be working from the same script — sell a centre-back or a left-back, and the money moves to Leipzig.