Barcelona are nearing an agreement with Ajax for wonderkid Matthijs de Ligt, who is said to be convinced to make the move to the Camp Nou.
The 19-year-old has attracted interest from many of Europe's biggest clubs as a result of his impressive performances in the Champions League. Teammate Frenkie de Jong sealed a €75m switch to Barcelona in January, and De Ligt could soon follow.
The source added: "As was the case with Frenkie de Jong, Ajax will warn [Barca] if any other clubs make a serious move for [De Ligt]."
The Blaugrana are keen to remain on good terms with Ajax and do not want to disrupt their progress in the Champions League, after De Godenzonen reached the semi-final of the competition with a dramatic 2-1 win over Juventus on Tuesday.
Club president Josep Maria Bartomeu has previously confirmed to ESPN that he knows what will happen with De Ligt, but insisted that nothing will be said until the summer.
Barcelona are said to be ready to part with around €80m to sign the 19-year-old in the summer, and they will finance the deal by selling a handful of players on the fringes of the first team. They are looking to raise around €300m, and could part with the likes of Philippe Coutinho, Samuel Umtiti and Ivan Rakitic in order to reinvest in the squad.
Thomas Vermaelen and Jeison Murillo are set to leave the club when their respective deals run out this summer, leaving space for a new defender in the team, and the club is said to have earmarked De Ligt, who netted the winning goal for Ajax on Tuesday, as the man to guide them to success in the future.