Manchester United manager David Moyes has told the club's fans to show patience as he looks to strength his squad in January transfer window.
In his programme notes for the Capital One Cup semi-final second leg at home to Sunderland, Moyes said he "will not compromise on the standards required" of a player joining United.
Reports that a bid has been lodged for Chelsea midfielder Juan Mata suggest a deal for the Spain international could be concluded in the coming days.
Moyes has stressed that his eagerness to add new quality to his squad will not see him make snap signings before the end of this month.
"I fully understand that supporters are keen to see us freshen up the squad with new faces, but January is a difficult month in which to bring people in," the manager told United Review.
"While we are actively scouting players all the time, a lot of the work we are doing now is preparation for the summer.
"If we can do any business now then we will certainly try to do it, but I will not compromise the standards required for a player that can come into this club and help improve it.
"We all know that our club is undergoing changes at present, but I have a clear path in my mind and I know where we are going."
United have been linked with moves for Newcastle's Yohan Cabaye and Bayern Munich defender Dante in recent days, but the capture of Mata would go some way to changing the current anxiety around Old Trafford.