Since his return from a loan spell at German side Werder Bremen, De Bruyne, Belgium's top scorer in qualifying for Brazil, has started only four matches for Chelsea and hasn't played a full 90 minutes in any.
Chelsea manager Jose Mourinho attended Belgium's 2-0 defeat to Colombia on Thursday, with De Bruyne a pale shadow of the dominant figure he was last season.
"For sure, playing at a World Cup without having been in action for a year, I think that's very difficult. I think for him that leaving and playing, that would be good," Hazard told Belgian public broadcaster VRT late on Sunday.
"If we want to get the best out of Kevin, I think that it's best if he leaves," he added.
De Bruyne, 22, has already been linked with a possible return to Germany's Bundesliga during the January transfer window, which would give him several months to return to top form by the time the World Cup kicks off in June.
- Sports & Recreation
- De Bruyne
- Werder Bremen
- Jose Mourinho