Barcelona found exits for two central defenders, Ronald Araujo and Alvaro Cortes, in the summer but, somewhat inexplicably, chose not to sign anyone for that position.
That leaves Flick with Pau Cubarsi, Gerard Martin and Andreas Christensen as his only natural centre-back options in the squad.
Both Eric Garcia and Jules Kounde are capable of playing in that position, but their services may be needed at right-back or, in Eric's case, even in midfield.
Now, according to SPORT , Flick continues to test Jules Kounde at centre-back in training ahead of the Valencia game.
The Frenchman has been used centrally in recent sessions, even though his strongest performances for Barcelona in recent years have largely come at right-back.
Kounde is naturally comfortable in central defence and has significant experience there, so the idea is hardly experimental from a technical point of view.
What makes it interesting is the timing.
Kounde was tried at centre-back in training. (Photo by David Ramos/Getty Images)
Barcelona are trying to build a squad capable of competing across every competition, and defensive flexibility will be essential over a long season.
Having Kounde available both at right-back and centre-back gives Flick more room to rotate without dramatically changing the structure of the team.
It could also help in matches where Barça need more physicality, recovery pace or one-v-one defending through the middle.
Kounde has not started the season as an automatic first choice, which naturally opens up questions about how Flick plans to use him.
That does not necessarily mean his importance has decreased.
In fact, his versatility may become one of his biggest strengths. A player who can cover two positions at a high level is extremely valuable when injuries, suspensions and fixture congestion begin to pile up.
Kounde needs to rediscover his best level for Barcelona this season. (Photo by Juan Manuel Serrano Arce/Getty Images)
The key will be whether Kounde can regain his sharpest form and force his way back into the side, regardless of position.
From Barcelona's perspective, this is the kind of internal solution that can save the club from needing to react in the market.
Flick always values defenders who can handle aggressive pressing and large spaces behind the back line.
Kounde fits that profile well, especially because of his pace and ability to defend away from his own box.
The only concern with the Frenchman is whether he can return to the level that made him one of the world's most promising defenders in his years at Sevilla and early years at Barcelona.
It remains to be seen whether Flick starts Kounde in central defence against Valencia alongside Cubarsi, and how the Frenchman fares on the night.
