The Swedish superstar broke down in April with a serious knee injury and was ruled out until January 2018.

United rejected the chance to hand him a 12-month extension at the end of a season that saw him plunder 28 goals to help Mourinho’s men win three trophies.

But Ibrahimovic, 35, has been doing his rehabilitation at the club’s Carrington base and still lives in Manchester.

Mourinho admits the door is still open for him to come back to United on a short-term deal and that he could be fit again in December.

Mourinho explained: “It’s possible. It’s open. We wanted to be honest and open for him to make a decision.

“There was not a new contract. There has been a time for people to think, feel and decide and from his family point of view he wanted to play football at the highest level.

“He didn’t want to hide behind such an amazing injury. He wasn’t happy with the way he finished the season, not playing.

“He’s challenged himself to keep playing at highest level. We’ve opened the door for him to recover with us and our people.

“At the same time, let’s make a decision that will make us all happy and if that’s for him to stay and us to wait until December, then maybe we will wait for such a good player,

“We are speaking and changing ideas. The important thing is the final decision being the best one for the club.”

Mourinho has signed Romelu Lukaku from Everton in a deal worth £100m and Swedish defender Victor Lindelof from Benfica for £31m.

But the United boss still wants to make two more signings, with Eric Dier, Nemanja Matic and Ivan Perisic still on his radar.

Mourinho, who admits United couldn’t agree a fee with Real Madrid for Alvaro Morata, added:

“We don’t have our door closed. We need more than Lukaku and Lindelof. We want four so it’s 50 per cent of the job done.

“But it’s so difficult. I wouldn’t want to be in Ed Woodward’s position because everything is so difficult.

“But we need more options for the squad. (Marcos) Rojo, (Ashley) Young and (Luke) Shaw might not be back to football until the end of the year, so we need two more players, or at least one.”