McCarthy, 24, made his name with Hamilton Academical before joining Wigan Athletic in 2009, featuring prominently under Roberto Martinez for the Latics.
It was therefore no surprise when McCarthy left Wigan in order to follow Martinez to Everton in 2013, and he was one of the Premier League's best midfielders last season as Everton finished in fifth place.
Whilst Everton have struggled for consistency this term, McCarthy remains one of the divisions top midfielders - but may now leave Goodison Park having not been offered a new contract yet.
McCarthy is allegedly 'angry' with the Everton hierarchy over a lack of contract talks, and could now decide to force a move away from the club this summer.
Two Premier League rivals are believed to be interested in McCarthy, with Manchester City and Tottenham set to battle for his signature if he does look to leave Everton, according to the Daily Mirror.
City may look to move on from Yaya Toure this summer and would therefore need another central midfield player, whilst Tottenham have relied heavily on Nabil Bentaleb and Ryan Mason in midfield this season, with manager Mauricio Pochettino potentially keen to add a little more Premier League experience to his midfield options.
Everton won't want to sell McCarthy without a fight, but with no immediate contract talks on the table, they risk losing him to a Premier League rival this summer.