A scan carried out this week showed the injury has worsened since De Jong first felt it during the World Cup in the United States, the midfielder revealed in comments to Barcelona's own media on Friday, delivered with clear frustration.
"We did a test and it showed the injury is now more serious than when I first got it in the United States," he said. "It was very hard because I wasn't expecting it. Nobody was expecting it. It really annoys me, because what I love most is playing football, especially for Barcelona and the national team."
De Jong explained the injury occurred by accident during training, when a team-mate landed on him and caused a minor knee problem.
"We did tests and it turned out there was a small issue. I was told I could keep playing, that I'd have some pain, but that I could continue. They assured me it couldn't get worse."
He continued playing through the World Cup and afterwards for Barcelona because, he said, "I love playing football. The World Cup is a dream and I would always do everything possible to play. I've done it many times at Barça too, and that's what I did."
The Dutch midfielder used the appearance primarily to push back against what he described as false reporting around his situation.
"We've drawn up a plan that everyone knows about and agrees with. I'm seeing a lot of things being said that aren't true, and I'm noticing that it's damaging my image."
He was particularly firm in denying reports of a poor relationship with head coach Hansi Flick.
"It's been said that my relationship with the coach is very bad, which is completely false. I have a very good relationship with the coach. I talk to him a lot. You can ask him. There are journalists who put out stories to be the centre of attention, even if they're false."
He issued an equally direct denial over his standing with the club — "that's also not true, because I talk a lot with people at the club, with directors and so on. I'd say my relationship with the club is very good" — and rejected a specific claim that he had refused to play against Atlético Madrid in last season's Champions League. "That's false. It's simply not true."
De Jong also addressed his recovery routine and the support he has felt from supporters despite the difficult period.
"I eat well, I make sure I sleep the hours I need, my whole family adapts around me. I do absolutely everything possible to come back in good condition as soon as possible. Right now I'm going through a hard time because I'm injured, but I can feel a lot of Barça fans supporting me. I think that should always be the general message — supporting each other, including when things go badly."
Looking ahead, De Jong, who has been at the club for seven years, said Barcelona's ambitions remain high both for this season and his own personal future there.
"It's always been my dream to play for Barça, and I still have dreams to fulfil here. We're very excited — I think we already have a very strong squad and we're reinforcing it well."
He also welcomed the club's new arrivals: "I think they're very good players and also very good people. They're going to help us a lot, and I'm trying to help them adapt as easily as possible."