The Ghana cap has been trialling with United for several weeks.
"We have not heard anything to that effect [that the club have agreed a deal]," said Shakespeare.
"It is an on-going situation, as reported before. There is no change in that.
"We are in constant dialogue with Jeff and Manchester United. Again it is a situation we are at ease with.
"It is open-ended but they are not going to keep him for six months and not make a decision. But at the same time, if we feel we need to use him here we will. It is all very relaxed."