United were criticised in some quarters for the sales of academy graduates Tom Cleverley and Danny Welbeck on deadline day, while eyebrows have also been raised about the club's aggressive use of the transfer market, after they spent around £150m this summer.
However, Phelan has claimed that the Dutchman is not looking at the long term after being tasked with restoring United to the top of the English game following last season's seventh-place finish.
He told reporters at the Soccerex convention in Manchester: "The Welbeck thing is just something that came at a certain time in the club's history and so people are saying the club has forgotten about its history.
"We've got a manager who is a proven winner, but it is a short-term thing for him. He has signed a three-year deal and is going to be here for that length of time.
"The club's priority now is to win things so, unfortunately, other things take a step back, but there are people working all the hours God sends to bring kids through."
United host Queens Park Rangers this Sunday.