The Republic of Ireland international was a success story at Everton last season after completing a £15m move from Wigan Athletic to Goodison Park.
If a club like Manchester United are interested, obviously you are doing a good job
The 23-year-old, who has also been linked with Arsenal and Tottenham Hotspur, scored one goal and made three assists in 33 Premier League appearances last season.
And McCarthy refused to rule out a potential big-money switch to the 20-time Premier League champions, who have also been linked with Juventus midfielder Arturo Vidal.
“If a club like Manchester United are interested, obviously you are doing a good job,” McCarthy told the Evening Standard.
“We will see what happens.”
McCarthy, who has 23 Republic of Ireland caps, revealed that he came close to joining Spurs before completing a move to the Toffees on the final day of last summer’s transfer window.
“Tottenham didn’t come up with the money but Everton did within the last couple of hours [before the transfer window closed]. Obviously it was just one of those things with Tottenham,” McCarthy added.
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