The Sun says the England Under-19 midfielder has fought his way into the first-team of the Dutch side.
But the Premier League champions are upset with his overall starts.
Mount, 18, is one of the top prospects from the Academy at Stamford Bridge.
There was hope regular football would put him in the frame for the first team.
But the teenager was not given a run in the team until last month when he got a chance in the Europa League and kept his place.