According to initial reports from Spain, Adidas are contemplating teaming up with United in an effort to fund a world-record bid for the Argentine.
The German sportswear giants are concerned by the damage United’s current lack of success could bring to their own brand and have allegedly identified Messi as a quick-fix solution.
“Lionel Messi is every season the same story, that he’s going to leave,” he said.
“Honestly, I hope he never leaves. I think he belongs to Barca and Barca belong to him.
“I think it would be beautiful for him to start and finish his career at Barcelona. I think he will stay but that’s just a personal opinion.”
Mourinho has confirmed that Zlatan Ibrahimovic will be staying put at Old Trafford for a second season, however.
The Swede joined on a one-year deal, as per United’s policy regarding players over the age of 30, but Mourinho indicated that United would be taking up the option of a second year.