Van Persie is in the last year of his contract at Old Trafford and has been linked with a host of clubs including Turkey's Fenerbahce who were approached in the winter regarding a potentially 'secret' deal.
"As early as January of this year, I received information from Turkey about Robin and Fenerbahce," wrote van Hooijdonk in his column in Voetbal International.
"The minute this information came, you knew that United had sent people to test the water for a move.
"Agents and others were searching for big clubs who are prepared to pay the high fee involved for van Persie. Robin's contract expires next year, so this is the moment when United can still get money for him."
Van Hooijdonk added: "Van Persie is in a difficult situation. To the outside world he says he is happy to stay and I can understand this. But Robin has the feeling that United want to get rid of him.
"A big club in England, Spain or Germany is a more attractive option. Until the player realises that behind his back the two clubs have done a big deal.
"That is the moment the pressure is put on. You are almost forced to go to the club where your employer has struck a deal. This is what I mean with games being played right now."