Boskamp insists Frenkie de Jong isn't ready to step in for Messi next season.
He said, “Frenkie, for example, is a fantastic football player, but to build a whole team around him? No, they will have to spend millions for that.
"If they have to buy players, I end up with Kevin de Bruyne. Also because Arthur has left and Kevin can be in his best position on the right in midfield. With De Bruyne you can go towards the level of the best years, but I don't see him leaving City."
Boskamp, commenting on new Barca coach Ronald Koeman's showdown talks with Messi, added: “That as a new trainer you say something like that to your best player. When he has said that, it has been whispered by the Barcelona board."