Manchester United and the case of Arturo Vidal grows ever more curious as the final fortnight of the transfer window begins. United have, up to now, declared they are not interested. That begs the question “if not, then why not”?

United’s line all summer has been that Louis van Gaal has absolutely zero interest in the Chilean. Opposing this is the view from Italy and Vidal’s homeland that the United manager does, indeed, admire the midfielder but that a combination of Juve’s asking price – £45m-plus – for a 27-year-old with scant sell-on value in three or four years’ time, and a knee problem, are making Van Gaal wary.

Earlier this month Jorge Sampaoli, Vidal’s national team manager told the Chilean newspaper El Mercurio: “United want Vidal but Van Gaal has doubts. Vidal was a great example during the World Cup in Brazil of not playing in the best of conditions. Manchester United want him, but what restrains his move to England for $80million is Van Gaal, who has doubts over his [knee] condition.”

On Juve’s summer tour Vidal has had a bespoke training routine as he continues to recover from the injury that sources in Chile have told the Guardian allowed him to be at only “60%” of his powers during the World Cup. As with Luis Suárez’s accelerated recovery from a knee problem, Vidal would not have played for Chile this summer if it had not been for the World Cup. Speaking about Vidal’s future on Monday, the Juve coach, Massimiliano Allegri, said: “It is normal that there are rumours about him: the great teams search for the great players. But Vidal is already in a great team.”

However, United’s reluctance to speak on the record about the player offers more of a clue. At last Friday’s press conference, before Van Gaal’s opening Premier League game as United manager, he instantly closed the subject down. “I’ll discuss it with Ed Woodward [the executive vice-chairman] not with you,” said the Dutchman.

Yet if Van Gaal is, indeed, not interested then why is that? The Guardian has tried on several occasions to establish the answer but no explanation has been offered. Again, on Monday morning, it was put whether the combination of Vidal’s knee injury and Juve’s asking price was deterring Van Gaal, without any light being shed.

If these are not the reasons then why is Van Gaal reluctant to pursue a dynamic box-to-box midfielder who is a proven force at one of United’s aristocratic continental cousins? Given the Dutchman said confidence had been “smashed” by Saturday’s defeat to Swansea, why are United not doing everything in their power to land a player who would instantly transform Van Gaal’s squad?

The holy grail this term is Champions League football. United players may line up to state the title is the aim but a return to the European Cup is what is demanded at all levels of the club.

Woodward knows the blue chip sponsors want the global exposure of Tuesday and Wednesday nights playing at the Theatre of Dreams and abroad, and Van Gaal is fully aware that attracting elite players is far easier if the Champions League can be offered.

At the weekend the 63-year-old was informing friends he still believes that the best footballers can be attracted despite the club not playing in Europe this season. He cited United’s pedigree, the salary on offer, and that players want to come and perform for him.

The clock is ticking on this hope. United believe the transfer of Sporting Lisbon’s Marcos Roja is close and he should shore up a vulnerable defence, but what Van Gaal desperately requires is an elite central midfielder. Against Swansea Ander Herrera, the £29m signing from Athletic Bilbao – who arrived over two months ago – continued the disappointing form he had shown pre-season.

Of that disastrous loss, Juan Mata wrote on his blog: “[The] US tour has produced two very positive weeks, both in terms of results and performance. But obviously those good feelings were to be transferred to the first official game. That’s what we wanted, yet we didn’t do it. We couldn’t manage to show what we had been working on in previous days. Swansea had a very solid game and things got tough for us after their first goal. We tied the game and had chances to score again but we didn’t take them, and later on we conceded a second goal and lost the match.”

A match that finished with Ashley Young as the left-back and Van Gaal forced to switch from his 3-5-2 to 4-4-2 indicates there are more problems than purely a midfield quality deficit. Yet Herrera, like United’s other summer arrival Luke Shaw, is not the finished article. As with Rojo, an established Argentina international who played all 120 minutes of last month’s World Cup final, Vidal is proven.

So, if not him for midfield, then who? The talk continues of Ajax’s Daley Blind and Real Madrid’s Angel Di María but while either signing would strengthen the team, neither of them is seriously influential in centre midfield. At the start of the summer United fans dreamed of Vidal, Cesc Fábregas and Toni Kroos. The image of these three midfield princes lining up in the 4-3-3 favoured by Van Gaal (for most of his career) had the congregation purring.

Yet after the manager decided against Kroos – who was then snapped up by Real Madrid for a bargain £20m – and against Fábregas, for whom Chelsea head coach, José Mourinho, paid £30m, Van Gaal has apparently made the same choice regarding Vidal.

With only a fortnight left of the transfer window, and following the defeat to Swansea, perhaps King Louis may yet change his mind about King Arturo.