The Portuguese did not elaborate on the Blues' pursuit of the England international and believes the Red Devils will improve under David Moyes' guidanceJose Mourinho has refused to address speculation regarding a fresh approach from Chelsea for Wayne Rooney.
Goal exclusively revealed in December that the 28-year-old has refused to enter negotiations with United over an extension to his current contract, which expires in 2015.
Chelsea launched two bids for the England international during the summer transfer window, while several clubs abroad are also monitoring the forward.
"I don't want to speak about it," Mourinho told reporters. "We play Man United in a few days. I don't think it's nice to speak about a Man United player.
"You have to ask him [Rooney]. You have to ask the player. And Man United because Man United has a contract with the player that doesn't end at the end of the season."
United head into Saturday's fixture against Swansea City off the back of three straight defeats, one of which resulted in an FA Cup third-round exit at the hands of the Swans.
The Premier League champions currently sit seventh in the table, 11 points behind leaders Arsenal, but Mourinho inists the club are in good hands with David Moyes.
"I don't think they have a problem," said Mourinho. "In this moment they are not top four in the Premier League, but they can be at the end of the season.
"A new manager, but a club with a fantastic culture of supporting the manager.
"I don't feel any problem for David. He works. Better results will arrive and he will be for many years in the club and will reach good results."