​According to Javi Miguel of AS, FC Barcelona are deeply frustrated with the way Frenkie de Jong’s knee injury was managed during the World Cup, with growing fears that the midfielder could now face between four and six months on the sidelines.The seriousness of the situation only became apparent on Monday, when De Jong unexpectedly reported to the Ciutat Esportiva ahead of schedule.AdvertisementAdvertisementAdvertisementAlthough the Dutch international had permission to remain on holiday until July 20, he returned early after experiencing significant discomfort in his right knee.Before undergoing medical examinations, De Jong met with Hansi Flick to explain the situation. Initial assessments by the club medical staff revealed a severely swollen and unstable knee, raising concerns that ligament damage may also be involved.Due to internal bleeding, however, doctors have been unable to carry out a definitive MRI scan, meaning a final diagnosis will only arrive once the swelling subsides.De Jong ended the World Cup with a knee injury. (Photo by David Ramos/Getty Images)AdvertisementAdvertisementAdvertisementWithin the club, there is a lot of anger towards Ronald Koeman and the Netherlands national team due to the information provided by them regarding the midfielder’s condition during the tournament.Barcelona were aware that De Jong had received painkilling injections before the matches against Tunisia and Morocco, but insist they were never informed that the midfielder’s condition had deteriorated to such an extent.There is now a growing belief inside the club that De Jong may have played through a significant injury against Morocco. With that match going to extra time, the Blaugrana fear the additional workload may have dramatically worsened the damage.Current projections suggest surgery remains a possibility. Should that prove necessary, De Jong could be unavailable for between four and six months.AdvertisementAdvertisementAdvertisementBarcelona’s frustration extends beyond the injury itself. Club officials are unhappy with Netherlands head coach Koeman, the national team’s medical department and, to some extent, De Jong himself.While they understand the desire to push through pain during a World Cup, they believe the player’s long-term health should have taken priority.Barcelona angry with Koeman. (Photo by Rafal Oleksiewicz/Getty Images)According to figures inside the club, allowing De Jong to continue playing under those circumstances represented an unnecessary risk that may now have serious consequences.AdvertisementAdvertisementAdvertisementThere is also lingering tension between Barcelona and Koeman dating back to the end of the 2023-24 season, when the Dutch coach publicly criticised the club’s management of De Jong’s recovery after an injury that ultimately ruled him out of the European Championship.Barcelona’s medical staff remain cautious until further tests can be completed, but optimism is in short supply.The Blaugran