De Bruyne was Belgium's top scorer in qualifying for next season's tournament in Brazil, which they are fifth favourites to win.
But he has started only four matches for Chelsea and did not complete any of them since returning from a loan spell with Werder Bremen last season.
Chelsea boss Jose Mourinho watched on as the 22-year-old played for his country in their 2-0 friendly defeat to Colombia on Thursday.
De Bruyne has already admitted he would be welcome to the idea of going out on loan again to boost his playing time and Hazard agrees he needs to be playing regular football ahead of the World Cup.
"For sure, playing at a World Cup without having been in action for a year, I think that's very difficult," said Hazard, whose Chelsea side face West Ham on their return to Premier League action this weekend.
"I think for him that leaving and playing, that would be good.
"If we want to get the best out of Kevin, I think that it's best if he leaves."
Another Chelsea player struggling to make an impression at Stamford Bridge is goalkeeper Thibaut Courtois.
The 21-year-old understudy to Petr Cech has been ever present for Belgium in the World Cup qualifying campaign and has helped Atletico Madrid, where he is on a season-long loan, to second place in La Liga.
Barcelona are said to be monitoring his progress and defender Toby Alderweireld, who also plays for Atletico, believes that is a realistic target for the man he claims could become the best goalkeeper in the world.
Speaking to Sky Sports News' Gary Cotterill, Alderweireld said: "He is incredible. He can do everything.
"He is good with the ball, he is good with his feet and he is great on his line. I don't think he has a weak point and I think he can be the best keeper in the world.
"I see him in training every day and I see him in games and I doubt there are any keepers better than him.
"He does not want to sit on the bench for eight games then play for one. He is very smart and I think it would be a good choice for him to maybe stay with Atletico, or go to another club where he will be number one."
And Colombia striker Radamel Falcao backed his former Atletico team-mate to go all the way when the pair met up for an international friendly last week.
"He is the best goalkeeper in the world, bar none," said the Monaco striker.
"That was very nice of him to say that," said former Genk keeper Courtois, who is remaining silent on his future despite reportedly being offered a new and improved deal by Chelsea.