London: Shinji Kagawa’s future at Manchester United has been plunged into doubt after Louis van Gaal admitted he was disappointed with the Japan midfielder’s performances.

Kagawa has been an unused substitute in the first two games of the van Gaal era at Old Trafford and the United manager even opted to leave him on the bench and send on winger Adnan Januzaj to play out of position in central midfield during the second half of Sunday’s 1-1 draw at Sunderland.

That was a major snub to Kagawa given his vast experience compared to the Belgian teenager.

And to make matters worse for the Japanese star, he has been cast into exile by van Gaal at a time when United are struggling with midfield injuries to Michael Carrick, Ander Herrera, Anderson and Marouane Fellaini.

Van Gaal tried Kagawa in one of the two central midfield holding positions he uses in his 3-5-2 formation during United’s pre-season tour of the United States.

But the 25-year-old failed to shine in that role and van Gaal has so far preferred Juan Mata in the more attacking central midfield berth than Kagawa played at Borussia Dortmund.

That has sparked rumours Kagawa could be set to leave United, with a potential return to German club Borussia Dortmund one mooted destination.

“Kagawa, I have tried to play him in that position in the United States [in pre-season] and he could not fulfil my wishes and my philosophy,” van Gaal told reporters after the Sunderland match.

“We have spoken about that and he is more of a 10.

“Juan Mata was playing at 10 and I thought I had to change the other players, which is why I chose to bring on Januzaj.

“It is because of creation. Kagawa can also create, but I asked Adnan to play there because of the lack of midfielders.”

United’s next match is Tuesday’s League Cup second round tie at League One minnows Milton Keynes Dons, and Herrera, who has an ankle problem, will have his condition assessed ahead of the match.

It is not expected that new signing Marcos Rojo’s work permit situation will be resolved in time for the former Sporting Lisbon defender to make his United debut in the fixture.

Meanwhile, Kagawa will be selected in the Japan squad for the first friendly matches under new coach Javier Aguirre, media said Tuesday, as doubts deepened over his future at Manchester United.

The Japan Football Association has informed the English Premier League side of the plan to call up the 25-year-old midfielder for friendlies against Uruguay and Venezuela on September 5 and 9, the Nikkan Sports daily said.

The Nikkan Sports said a couple of games with his countrymen might give Kagawa a sorely needed lift.

“There is a possibility that he will regain his confidence and game intuition by playing the two games as a member of Aguirre’s Japan,” the sports daily said.

Italian coach Alberto Zaccheroni resigned and was replaced by Aguirre after a poor World Cup in Brazil.

But the paper warned the former Cerezo Osaka star should not expect any special treatment under the famously demanding Mexican.

“Aguirre is not a person who prioritises names,” it said.

Kagawa, signed by the now-retired Alex Ferguson on a four-year deal in 2012, has played 56 times for United, scoring six goals, though he failed to find the net in the 2013-14 campaign.