After another dismal Manchester United performance against Sunderland on Sunday came a Louis van Gaal revelation regarding his desperation to solve the dearth of central midfield talent at the club. “Kagawa – I have tried to play him in that position in the US and he could not fulfil my wishes and my philosophy,” the manager said of an experiment with the Japanese on the summer tour. “We have spoken about that and he is more of a No10. Mata was playing at No10 [at Sunderland] and I thought I had to change the other players, which is why I chose to bring on Januzaj.”

Van Gaal thereby signalled that Shinji Kagawa’s United career may be in critical condition and also illustrating why Ángel di María may be a £60m red herring. The Argentinian is a fine footballer, a member of the elite band below Lionel Messi and Cristiano Ronaldo, but he is no chief conductor of central areas.

To audition Kagawa for the role shows, in one stroke, Van Gaal’s assessment of Tom Cleverley, Marouane Fellaini, Darren Fletcher, Anderson and Ander Herrera as a squadron, and illustrates where the manager feels he really should strengthen.

To compound this Fellaini, Herrera and Anderson, plus Jesse Lingard, the forward Van Gaal is forced to deploy further back, are all unavailable. Michael Carrick, another central midfielder, is also injured. This caused the use of Adnan Januzaj – a No10 or wide man – in the engine room when the Belgian entered the fray in the 63rd minute of Sunday’s 1-1 draw.

“It is not usual that we have four injuries in midfield,” Van Gaal said. “Every club that has that has a problem. That is why I played Januzaj in midfield because as a coach I want to win. I have said that we need creative passing and I thought Januzaj could provide that. That is the reason.

“It is because of creation. Kagawa can also create, but I asked Adnan to play there because of the lack of midfielders. When he played in Belgium, he played in midfield so I asked if he could do it for us. I said to him: ‘You are on the bench as a midfielder,’ because I want him to focus. He played there and you could see it’s not so many times that he’s played there. But he did his utmost and I cannot demand more.”

The United midfield problem is not new. Doctorates could – and maybe should – be written about how and why it is yet to be resolved. Van Gaal joins Sir Alex Ferguson and David Moyes as managers who, since Roy Keane and Paul Scholes faded and Owen Hargreaves suffered a career-hobbling injury, have found the problem a puzzle.

The word is that Di María, a wide player by instinct, could be moved inside though into the No10 position at present given to Juan Mata by Van Gaal. Yet even here doubt hovers. “At this moment, we have five No9s and four No10s and don’t have wingers to give us attacking width,” the Dutchman said a couple of weeks ago, before describing Di María as a winger of the “highest level”.

This suggests Van Gaal is not paying a British record fee for Di María to be a fifth No10. So where will he play? As a wing-back in the 3-5-2? If not then in a 4-3-3, maybe?

The conundrums keep coming. Van Gaal switched United from a traditional four-sentry defence to a three centre-back system to accommodate the attacking trident of Robin van Persie, Wayne Rooney and Mata. To tear this plan up after a summer-long bedding-in period and the season’s opening matches may confuse a squad Van Gaal is adamant requires three months to adjust to his methods, as the 63-year-old retrains them to use “brains” rather than instinct.

A glance at United’s competitors shows how all harbour midfield gold. Manchester City boast the A-lister Yaya Touré, plus Brazil’s World Cup player Fernandinho, as well as Frank Lampard and Fernando. The latter was a £12m summer bargain from Porto and precisely the ilk of midfielder United should be acquiring.

At Liverpool, Brendan Rodgers has a Premier League great, Steven Gerrard, supported by Jordan Henderson, Lucas Leiva, Adam Lallana and Joe Allen, plus the potential of Emre Can. Chelsea have two gun midfielders in Cesc Fábregas and Nemanja Matic, who are complemented by Ramires and Mikel John Obi. And how Van Gaal might like to choose from Arsenal’s Aaron Ramsey, Jack Wilshere, Santi Carzola, Mikel Arteta and Mathieu Flamini. Or even Alex Oxlade-Chamberlain, who Arsène Wenger believes will one day be a deep-lying maestro “very similar to Steven Gerrard”.

Against Sunderland Van Persie and Rooney were starved of chances. Even Phil Jones hinted at the lack of creation. “We were dominant in possession and created glimmers of chances, but never really carved them open like we would have liked,” he said. “We need to keep working on everything.”

The hope is that the closing week of the window will prove to be a particularly long time in the club’s transfer fortunes. Juventus’s Arturo Vidal, Milan’s Nigel de Jong and Ajax’s Daley Blind, who is also a defender, are on Van Gaal’s radar. Any of these trio’s signature would strengthen midfield and transform hopes.

United would arrive at 2 September having ended the summer by adding Luke Shaw, Herrera, Marcos Rojo, Di María (assuming that he arrives) plus AN Other midfielder.

The continual line of players offering post-match promises to improve next time could then end. “We dropped two points today,” Van Persie said post-Sunderland. “We were a bit too sloppy in possession, and in that sense we made it too hard for ourselves. We’ve played two games and only picked up one point. We would have loved to have got six points but it didn’t happen, so we have to bounce back.”

• This article was amended on 29 August 2014. Because of an editing error, the names of Frank Lampard and Fernando appeared in the wrong order, leading to the implication that it was Lampard who was a £12m signing from Porto.