De Bruyne, 22, scored four times to help Belgium top their World Cup qualification group yet has been a peripheral figure at Chelsea, making just two Premier League starts so far this season.
And Hazard feels time away from west London for De Bruyne, who spent last season on loan at Werder Bremen, is vital.
“If we want to get the best out of Kevin I think that it’s best if he leaves,” said Hazard. “Playing at a World Cup without having been in action for a year is very difficult.
“I think for him that leaving and playing would be good.”