United are braced for De Gea to leave the club with Real lining up a move to take the 24-year-old back to Spain this summer.
Louis van Gaal has already admitted the club are looking at alternatives in case De Gea does leave Old Trafford.
And Schmeichel insists that United will be active in the transfer market to improve the squad at Van Gaal's disposal irrespective of what De Gea decides.
It will never be about one player, it's not just about David de Gea.
Peter Schmeichel
He told Perform: "Clearly there's an issue where either himself or his girlfriend wants to go back to Madrid and you can't argue that Real Madrid isn't as big a place as Manchester United - some would say bigger.
"If he wants to go, he's done fantastically well for Manchester United. We should be thanking him and we, of course, will move on.
"I think the most important thing for Manchester United is that we have a positive transfer window and we get players in that can take the club forward. It will never be about one player, it's not just about David de Gea.
"If he wants to continue playing [for us], we'll be very happy with that. If not, we move on and the manager will take decisions on who takes over but we need more than one player - everybody knows that.
"Hopefully we have positive messages coming in terms of players coming to Manchester United and we build an atmosphere and spirit where we can move on and challenge for trophies again."