Striker Ibrahimovic is a free agent but it now recovering from knee surgery at the club's training ground.
Asked about a possible reunion with Matic, who played under him during his second stint at Chelsea, Mourinho replied: "I can't say any word about a player who is a Chelsea player".
"We want him to be honest and open and let everything be there for him to make a decision in case his desire was to leave, so there was not a new contract. We are speaking and changing ideas".
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Jose Mourinho has refused to discuss potential interest in Nemanja Matic, but insists he wants more Manchester United signings before deadline day. We are not happy with just Lukaku and Lindelof. He was not happy in the way he finished the season. "We wanted four - 50% of the job is done".
However, Ibrahimovic is being aggressively pursued by LA Galaxy, who wanted him when he left PSG a year ago, and are prepared to make him the highest paid player in the MLS.
Both Los Angeles-based Major League Soccer clubs are interested in signing Zlatan Ibrahimovic if the Swede decides to end his career outside Europe. Let's hope we seem him back in action in a shirt of his own choosing soon.
LA Galaxy manager Curt Onalfo did admit the "DNA of the Galaxy is to attract world-class players, so we are always looking for one" so Ibrahimovic would certainly fit the profile of the transfers they need to make.