Several English newspapers on Tuesday claimed PSG are hoping to finalise a £45m deal for Di Maria before he joins United’s pre-season tour of the United States.
Van Gaal last week stopped short of guaranteeing Di Maria would be part of his squad this season, and the United manager was again asked about English football’s most expensive player in the wake of a 3-1 victory over San jose Earthquakes.
He said: “When we think we have something then I shall say it, but he shall come here on July 25.”
That is the day United are due to face Barcelona in Santa Clara – and five days before their US tour concludes against PSG in Chicago.
Di Maria has been on leave since the Copa America, where he was part of the Argentina squad that finished runners-up to hosts Chile.
Van Gaal, meanwhile, has backtracked on claims United are “in the process” of pursuing a striker “not written” about by the media.
Asked about a possible interest in Juventus’ Fernando Llorente or Thomas Muller of Bayern Munich, he told said: “I don’t know if I want to buy a striker, because I have read in the media that the striker is a surprise.
“No! That I didn’t say. You are saying that because my answer is like that. No! I mean something else…”