The Republic of Ireland international only moved to Goodison Park on deadline day on September 2 last year when he followed Roberto Martinez from Wigan.
He played a starring role in his debut campaign as Everton claimed fifth place in the Premier League to secure qualification for the Europa League.
McCarthy’s role in Everton’s terrific season has not gone unnoticed and, although Louis van Gaal is being linked with a string of foreign signings as an overhaul of United’s squad is widely anticipated, one of his key signings could be from a North-West rival.
Everton are keen to open talks with the 23-year-old over a new deal, but news that United could be ready to make a move may scupper that idea.
Sources have confirmed to Sky Sports that United may even try to offer Tom Cleverley in exchange as Martinez is known to be fan of the England midfielder and it appears he could be one of a number of Old Trafford regulars allowed to leave this summer.