Louis van Gaal has said Shinji Kagawa does not want to play his brand of football as he explained the Japan international's absence from the Manchester United team this season.
Kagawa has been an unused substitute in both Premier League games, even though Van Gaal has faced what he called the worst injury crisis of his managerial career, with nine players sidelined and new signing Marcos Rojo ineligible to make his debut in Sunday's 1-1 draw at Sunderland.
The Dutchman played Kagawa as one of his two central midfielders during United's preseason tour of the U.S.
But he told his news conference at the Stadium of Light: "Kagawa did not wish to fulfil my wishes, my philosophy, when I played him in the United States."
Juan Mata has been operating in Kagawa's preferred position behind the strikers, with Van Gaal explaining in July: "Kagawa was a No. 10 at [Borussia] Dortmund, but I want to try him at No. 6 and No. 8."
While United have made a slow start under Van Gaal, collecting a solitary point from their first two league games, Robin van Persie believes good results will soon come.
Van Gaal has changed United's system to play 3-4-1-2, but Van Persie believes the manager makes his instructions easy for the players to understand.
The 31-year-old, who made his first appearance of the season at the Stadium of Light, captained the Van Gaal-managed Netherlands team that finished third in the World Cup.
He told Sky Sports: "I worked with him for two years, and he's very clear. He's clear in what he asks of each player in the team every day. So, where I can, I will help the other players.
"I think that everyone has faith and everyone believes in the staff and players. We have great players, and it's just a matter of time before the points start coming in."