The Republic of Ireland international only joined the Toffees from Wigan last year and was impressive in his debut season on Merseyside as Roberto Martinez’s men mounted a charge for Champions League qualification.
His displays in the blue shirt have now attracted both United and Spurs, who may make serious moves for his services before the new seasons starts.
Everton are desperate to keep hold of the man who starred alongside Gareth Barry last season and are reportedly holding out for at least £25m for his services.
United have been tracking McCarthy since David Moyes was in charge, and Louis van Gaal is also said to be a fan.
Mauricio Pochettino has been given the green light by White Hart Lane chiefs, with his hopes of getting Morgan Schneiderlin to follow him from Southampton looking slim with Arsenal keen on the Frenchman.
The Gunners themselves are keen, but a move appears unlikely.