Louis van Gaal has admitted he is worried that David de Gea's delay in signing the lucrative new contract Manchester United have offered him means he is likely to reject it.
Real Madrid target De Gea's current deal expires in 2016 and United risk either losing the goalkeeper on a free transfer next summer or being forced to sell him this year to prevent an £18 million buy departing without compensation.
The Manchester club are keen to keep the Spain international but manager Van Gaal realises he is powerless to prevent De Gea from spurning their generous offer.
"It takes a long time now," Van Gaal said in a news conference. "So ... it can always happen. I am not the boss. I want him to stay. The player is the boss he can say yes or no. You will have to ask David de Gea not me. He has to sign. We have offered him a lot of money."
Van Gaal signed six players last summer but four of them -- Angel Di Maria, Marcos Rojo, Daley Blind and Radamel Falcao -- only arrived in the final weeks of the transfer window.
United are interested in PSV Eindhoven winger Memphis Depay and Borussia Dortmund defender Mats Hummels amid talk they are moving now to get both players.
And Van Gaal said he preferred to recruit early in the summer if possible, adding: "Of course it's an advantage but it's also dependable on the market, which players are free, which players want the clubs in the world to sell. It's not so easy and I don't want to buy every player."
United visit Everton on Sunday and Van Gaal said he is not concerned that Marouane Fellaini will lose his cool when he faces his former club.
"I am not worried about Fellaini's behaviour," he said. "Up to now he is composed."
Van Gaal has used players in some unexpected roles this season, when Di Maria had a spell as a striker, winger Ashley Young has been used at left-back and captain Wayne Rooney has often been deployed in midfield.
Van Gaal explained he has often been willing to experiment during his long career, saying: "I have changed a lot of players' positions also. I have made strikers into central defenders and No. 10s into full-backs because I have to look at the qualities of the players and then I shall ask if you want to play in that position because I think you can do it.
"Edgar Davids was a left winger and I made him a left midfielder and he has played his whole career there at a high level. Carles Puyol was a right winger and I said you have to play right full-back and I said can you do that for me. I can mention a lot of players.
"Michael Reiziger was a No. 10 in the youth team at Ajax and I said you have to play right full-back for me.
"Fitting in the profile is the answer to everything and the player has to do that and wants to do that. Fellaini is always doing what I ask. He is trying to do what I ask."