The 23-year-old centre-back is expected to join Eric Bailly as the Red Devils' regular defensive combination after completing his £31 million move from Benfica, but Mourinho is looking to ease him in slowly as he adjusts to the new league.
Inter's sporting director insists that neither Perisic or Antonio Candreva - wanted by Chelsea - are for sale.
"I don't understand where some of these stories come from, ' Ausilio told Mediaset Premium on Thursday night". The two-time Champions League victor still wants three more signings - two full-backs and a wide player - but is understood to have accepted that one new face might be the limit of the club's remaining activity this summer.More news: Tillerson To Travel To Philippines, Thailand, Malaysia: State Dept
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"He has said: 'Perisic is an important player and we're now discussing a new contract with him'".
"There has been no more significant contact in the last few weeks", Inter boss Luciano Spalletti said, before their Saturday victory against Chelsea in Singapore. "The team is important not one player".
The Italians have also been linked with Bayern Munich star Arturo Vidal, but Ausilio said: "We realised straight away that it was practically impossible to get Vidal, because when Bayern don't open the door, you've got no chance".
"We intend to keep Candreva".
"We need options. Lukaku, Martial, Rashford - all of them are different players".