The Belgian winger recently matched Gianfranco Zola's 80-goal record for the Blues and, having now fully recovered from injury, is once again an integral part of Antonio Conte's starting XI.
And Desailly is of the opinion that Chelsea would be able to manage without their talisman, insisting that they coped previously when Didier Drogba left the club and that they would find a replacement.
"We are still in the season, no player is more important than the club," he told Goal . "Even when Drogba left, one of the great players, the spirit of the club continued. They continued to win.
"We will be sad if Hazard has to go but I am sure that Roman Abramovich is still passionate about the club. He will bring in another player that can allow the club to be at the same level again."
Meanwhile, Chelsea boss Conte insisted he has given up on retaining the Premier League crown following the 1-0 defeat to West Ham last weekend and, with Barcelona to follow in the Champions League, Desailly is concerned about the recent run of form.
"Chelsea lost to West Ham recently so the side is not in the best shape," he added. "They need to use the league to psychologically recover from this defeat and be in good shape come February when the Champions League starts [again].
"They can then recover from the past mistakes and show they have the capacity to become one of the leading sides in England and Europe. From what I have seen I think Manchester City have something more than any other team in Europe today. You see that by their 11-point lead on all the others.
"Maybe their dominance now won’t be the same in February. Napoli were like City earlier [in the season] but they have since dropped physically and then dropped points so I think everyone is hoping City have that [kind of] drop so they won’t be this good in every game.
"Last season was the best season for Chelsea to win [the title]. City weren't that good, they weren’t ready for the philosophy of Pep Guardiola. Manchester United were not at the top level and didn’t have all the top players. Tottenham didn’t have enough of a winning mentality.
"Arsenal have always had problems during the season, so last season was a special year for Chelsea to win it. This season there’s a lot of new players; Alvaro Morata, Tiemoue Bakayoko, Danny Drinkwater and Davide Zappacosta.
"Even Marcos Alonso, Andreas Christensen and Victor Moses coming in, they need to maintain their level across more fixtures. That can be the difference but it is just a matter of time to get back to that level that they had before.
"Bakayoko has not given his full potential. Nemanja Matic was already comfortable at Chelsea and was embedded in the system so it was easier for him but I think that they potentially have the squad to win things. Willian and Pedro want to be in their national squads for Brazil.
"Hazard is in form and scoring goals so Chelsea need it all to come together collectively to be at a high level when they face Barcelona."
Desailly won the World Cup with France and he is a two-time Champions League winner. He joined Chelsea in 1998, making more than 200 appearances and winning two cup competitions in the years prior to Abramovich's takeover of the club.
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