Everton are concerned that star striker Romelu Lukaku could leave Goodison Park for rivals Manchester United this summer, reports the Daily Mirror.
The Belgian has been strongly linked with a move away from the Toffees at the end of the season on the back of what has been a hugely underwhelming campaign for Everton.
A host of teams across Europe have been courting the young Belgium international, who has netted 18 league goals this season.
The player himself has previously admitted that he wants Champions League football, but Everton are worried he could still sign for United even if they fail to secure a top-4 finish this term.
The potential appointment of Jose Mourinho is believed to put United in pole position to secure the services of Lukaku, with the young striker insisting there is no animosity between the two.
However, United would face competition for his services from the likes of Bayern Munich, Real Madrid, PSG and Napoli should Everton reluctantly cash in on Lukaku.
For more stats on Romelu Lukaku, click here to view his WhoScored player page