United have seen a bid of £70m turned down for the 26-year-old and the clubs are still in discussions over a transfer, with the Foxes holding out for closer to £85m.
A deal is expected to go through, and is now reportedly in its final stages, but according to the Sun, Maguire is frustrated with Leicester vice-chairman Khun ‘Top’ Srivaddhanaprabha for letting the transfer drag on.
The England international signed a new contract with the club last year, but it was agreed that the Foxes would let him go if a reasonable price could be agreed this summer.
Maguire has made it clear that he would like to challenge himself elsewhere and feels that the club are dragging their heels on the ‘gentleman’s agreement’ that they made.
The former Hull City and Sheffield United man called in sick for training on Monday, the second time he has missed a session this summer, but says it was due to a stomach bug and not because he is pushing for a move.
United are expected to come back with an improved offer on the £70m they originally produced, one that will make Maguire the world’s most expensive defender, surpassing the £75m spent on Virgil van Dijk by Liverpool in 2018.
Both Manchester United and Leicester get their Premier League campaigns underway in less than two weeks, with United facing Chelsea and the Foxes taking on Wolves on Sunday 11 August.
Leicester are thought to be interested in Burnley’s James Tarkowski and Brighton’s Lewis Dunk as possible replacements for Maguire.
United are looking to improve on their options in central defence, which currently stand at Chris Smalling, Victor Lindelof, Phil Jones, Eric Bailly, Axel Tuanzebe and Marcos Rojo.