Louis van Gaal refused to comment on Danny Welbeck's future as speculation mounts the England striker is set to leave Manchester United.
Press Association Sport understands Welbeck, who joined United in 2007, has been told he can depart Old Trafford.
The 23-year-old started the majority of the club's pre-season tour of the United States, but he is unlikely to jump ahead of Wayne Rooney and Robin van Persie in the pecking order, and is therefore free to go.
In a heated press conference at the club's training ground, Van Gaal refused to confirm or deny the story, but the new United manager admitted he was angry that details of a private conversation he held with Welbeck had been leaked.
Van Gaal said: "The media were not in the room and I do not speak about that because that's private.
"I know what I said to Danny and Danny knows exactly what I said to him.
"I assume that Danny Welbeck is not saying anything about our conversation and also in that conversation was (assistant manager) Ryan Giggs and he doesn't say (anything) either, and that is the way it should be."
The decision to allow Welbeck, a local boy who worked his way through the ranks at Old Trafford, to go will come as a surprise to some United fans, particularly as Van Gaal does not have a strong selection of strikers to choose from.
Javier Hernandez is the only other senior striker available to the Dutchman, and he has been linked with a move away from the club.
Van Gaal is determined to streamline his squad though, and it is understood that up to 12 players have been informed they could leave.
For the first time since taking over as manager, Van Gaal cut an angry figure as he addressed the media at the AON Training Complex at Carrington.
The former Ajax manager, who lost his first Premier League game to Swansea last week, has been bemused by some of the criticism he has received for a lack of transfer activity.
"Two weeks ago I was the king of Manchester and now I am the devil of Manchester," Van Gaal said.
The only signings through the door so far are Ander Herrera, Luke Shaw and Marcos Rojo.
All three have potential but they are not yet in the same league as the likes of Cesc Fabregas, Toni Kroos and Diego Costa - all of whom were available earlier in the summer.
Van Gaal remains to committed to signing new players before the transfer window shuts a week on Monday.
The club have privately distanced themselves from reports they are close to signing Angel Di Maria from Real Madrid.
Dutch duo Kevin Strootman and Daley Blind are on Van Gaal's shortlist, while Sami Khedira appears to be another option after he requested to leave Real Madrid.
But if United fans were hoping for some assurance from their manager over new signings, then it was not forthcoming.
"It's not so easy to buy and sell in the football market," Van Gaal said bluntly.
Instead, Van Gaal's insists United's supporters need to be patient.
"It shall be difficult in the first three months," he said.
"I have said that to (executive vice-chairman) Ed Woodward and (owners) the Glazers,
"I am hired to build up a team and that is a process and that process needs time.
"You have to believe in the philosophy that we make again a big club but it needs time and it's not an overnight job."
In fact, Van Gaal says he would understand it if supporters shared the view of Paul Scholes, the former United midfielder who said he was "genuinely scared" about the club's future this week.
"I can imagine that fans are also scared," the 63-year-old said. "Because they have seen what happened last year and they have seen the first match (this year).
"But also they have to believe in the philosophy that we bring into this club and the players are believing that.
"They have shown that in the US, but they need to show it here.
"They need time. And also Paul Scholes needs to believe in that philosophy."