Macari told MUTV: "If something crops up Sir Alex will be the first to tell his directors 'there is a chance here'.
"What we don't know is whether Sir Alex Ferguson fancies Michael Owen. I know he fancies Wayne Rooney because I think that is the general opinion and most people think he is a star of the future.
"I wouldn't rule them out but at this moment it would be a little bit foolish to jump in so early.
"If Ruud and Louis Saha were going to be three or four months away, we know about Ole and he is a year away, then you have to go and do something, but I think the manager has indicated he is going to weigh things up more or less day by day, and if he feels they are going to be out for a while you can expect him to move into the transfer market."