De Jong is seen as the brightest midfield prospect in Europe and earmarked as a replacement for Fernandinho, who turns 34 this year.
The 21-year-old Holland worldwide was on Pep Guardiola's summer transfer wish list, so his £75 million move to Barcelona is not particularly good news for City.
Speaking about De Jong's move to Barça, Guardiola said: "I said many times - Barcelona and [Real] Madrid: it's impossible to fight against them, for the prestige, the incredible league, the incredible clubs they are".
The Netherlands midfielder is to move to the Nou Camp in a £65million deal in the summer, with the player reportedly set to earn around £300,000 per week.
The midfielder has scored four goals in 16 Eredivisie appearances so far this season.
As explained by AS, "De Jong was shown messages from Neymar to people in the Blaugrana club in which the Brazilian complained about the low competitiveness of the league, the hardness of the rivals or of the weather and in those who recognized that he had made a mistake by leaving Barcelona".
The Netherlands global was also a target for Manchester City and Paris Saint-Germain, but opted for Barcelona.
"I am not disappointed in him [De Jong]", he said. The players have to take their own decisions.
He eventually quit Stamford Bridge for Real Madrid and subsequently joined Bayern Munich, where he has been since 2009 and will leave at the end of the current campaign.
Boateng and De Jong, who will join in July, follow Jeison Murillo from Valencia, and Jean-Clair Todibo from Toulouse.
"These are just the insane sums going around in football nowadays".
"Given that information, De Jong was very clear and signed for Barca for a money that nearly certainly prevents Neymar from returning". "Barcelona have always been a dream club for me".