While United are not discounting looking abroad in their search for a new lynchpin, the club would prefer Premier League experience.
Deciding to go for proven players would certainly limit United’s options, and ultimately increase the finances attached to those deals.
Baleba, Wharton and Tonali are also among the players United’s recruitment team have discussed and will continue to explore.
One well-placed source has told BBC Sport that, via an intermediary, United have made a tentative enquiry about Brighton midfielder Baleba in recent months.
However, any successful move for the Cameroonian will depend on Brighton’s valuation, which reports suggest is £100m.
While United accept they will have to make a massive financial outlay to land one of their preferred midfielders, whether they would be willing to match the sort of fee Brighton will be looking for is in question.
Crystal Palace’s Wharton is certainly admired at United, but whether he fits the sort of central-midfielder profile the club are looking for is unclear.
Wharton is viewed as a player who benefits from having runners alongside him in midfield, allowing him to execute the passes that have become synonymous with his burgeoning reputation as one of England’s best emerging midfield talents.
Palace have explored the possibility of offering Wharton – whose contract has three years to run – a new deal with a release clause in the hope of securing his future before next season.
Similarly with Tonali, Newcastle have a history of making things difficult for clubs interested in their players. Just ask Alexander Isak and Liverpool.
But there is a suggestion the Italy midfielder is open to leaving St James’ Park this summer, with his representatives understood to be scoping out the market to ascertain which clubs may be interested in him.
Outside the Premier League, Atalanta midfielder Ederson is among the players in Europe who club recruitment staff have identified as having potential.
There is a world in which United look to sign two number sixes, particularly if Manuel Ugarte leaves Old Trafford – which is possible this summer – though in such a scenario it is very likely the second capture would be rotated more than their primary midfield signing.
Rasmus Hojlund and Marcus Rashford’s expected exits this summer will help supplement United’s transfer budget, which will also need to stretch to signing a left-winger and potentially a central defender, though that would depend on the outcome of the out-of-contract central defender Harry Maguire’s talks over a new deal.
But the number six is set to be the big one to watch.