Tottenham Hotspur are understood to be demanding a fee in the region of £70m from Manchester United for Toby Alderweireld - partly because of Liverpool defender Virgil van Dijk's winter transfer to Merseyside.
The Belgian defender has been linked with a move away from the north London club throughout the season, with much of the transfer talk focussing on a £35m release clause that Alderweireld has written into his contract.
That valuation doesn't come into effect until next summer though - with ESPN reporting that Spurs are holding out for double that amount currently, because they believe his ability to be similar to that of Liverpool defender van Dijk.
The Dutchman moved to Anfield for £75m in January, and Spurs chief executive Daniel Levy believes that price reflects Alderweireld's market value also - much to the chagrin of bosses at Manchester United.
Despite Spurs' strong stance on the defender's price, there remains incentive to sell Alderweireld this summer, with the Belgian having only two years remaining on his current contract.
The ongoing saga with Alderweireld has not dampened the Red Devils start to the summer transfer window though, having already brought in Brazilian midfielder Fred from Shakhtar Donetsk and highly rated 19-year-old full-back Diogo Dalot from Porto.
Assuming United are unable to agree a deal for Alderweireld in a timely fashion, it is likely they will look elsewhere for defensive backup, with Sevilla's 22-year-old French defender Clement Lenglet being identified as an alternative, despite reportedly being on the verge of signing for Barcelona.
Real Madrid's Raphael Varane and Bayern Munich's Jerome Boateng have also been highlighted as defensive options for United in the transfer market, with Jose Mourinho understood to be a big admirer of the defensive duo.