Manchester City are holding talks with Everton over the possible signing of defender John Stones.
The Daily Mail says City will offer £50m ($66m) for the England international after having a £40m bid rejected earlier this month.
Stones is reported to have his heart set on leaving Goodison Park for the Etihad as he wishes to work under Pep Guardiola.
Toffees boss Ronald Koeman has told Stones's representatives that the player should decide whether he wants to stay or leave as soon as possible.
A £50m move will make Stones the most expensive English player in history ahead of Raheem Sterling.
Barcelona and Manchester United have also been linked with the centre-back, who is contracted to Goodison Park until 2019.
Stones is still highly coveted by Europe's top clubs despite coming under criticism for his performances for Everton this season.
He has made 77 league appearances for the Toffees and was included in England's Euro 2016 squad, although he did not make an appearance in the summer tournament.
United boss Mourinho tried to sign Stones at Chelsea last summer but Everton rejected all transfer bids from the Blues for the player – the highest amounting to £37m.
Guardiola is understood to admire Stones for his ball-playing ability and technical proficiency.
"I think by August 31 we will have the right players to play the way we want," the Catalan coach was quoted as saying by the Daily Mail.
"At the end of the window, we will have to see which players we have. But I think a lot of the midfield players we have here can play at the back. When that happens, the build-up play is much, much better."
Stones played the final 30 minutes of Everton's pre-season friendly win over MK Dons at Stadium mk on 27 July.