Barca is in a rotation of players in their defense. they had been strong at the start of the season. but to play consistently, of course, it is impossible for players in the Barca main squad with so many matches.
Barca now has a weakness, and Xavi will of course have to take this into account for the winter transfer window. looking for a formidable defender to become a strong fortress of Barca.
The mainstay players from Barcelona are not able to play consistently because it requires very high energy to guard at the back which is very vulnerable to opponent attacks, Many defenders are injured because of the previous game, therefore Xavi must carefully consider the formation for each game so that get good results.
The problem Xavi is facing is the same problem that Manchester United coach has avoided. Xavi keeps relying on the Old strength for his defence and midfield and also relying on their experience to play some tough and high pressing matches. that is why he gets low result in some important matches, if he does not have the guts to bench Basquet and play de Jong in that midfield he will not make good results . he needs to Leverage on the strength of the young player to win matches when it is important.