The Blues star man, whose 16 league goals last season helped the club to their second league title in three years, was initially believed to have suffered a twisted ankle during a training session at the National Football Centre in Tubizeon, Belgium on Sunday (4 June).
However, a scan later showed that Hazard had actually fractured his ankle and could be sidelined for six to eight weeks, missing the Czech Republic and Estonia matches this week.
The news comes as a blow for Antonio Conte and his Chelsea side as the upcoming 2017/2018 season begins in 10 weeks.
The west London club have pre-season games against Arsenal, Bayern Munich and Inter Milan and a Community Shield game against the Gunners as well, likely to take place the weekend before the season begins on 6 August.
There is also no guarantee that Hazard will be back to full fitness after recovering from a fractured ankle as he might have to be gradually bedded into the team upon his return.
As for the Belgian national team, the news is not that much of a blow as they currently sit first in their World Cup qualifying group with 13 points from five games in Group H.
Maintaining a two-point lead over second place Greece, the Euro 2016 quarter-finalists travel to fifth place Estonia on Saturday (10 June), having beaten the hosts 8-1 in Brussels back in November.