The 28-year-old lasted just 22 minutes of the Champions League fixture with Malmo after coming under a heavy challenge in the penalty area.
According to The Sun, Lukaku may be forced to miss up to four weeks with a twisted ankle, half of that time coming during the international break.
Should the report prove to be true, the summer signing will miss five matches in quick succession before being on the brink of a return during the middle of November.
Chelsea face a triple-header of Leicester City, Juventus and Manchester United in the seven days after the next international break. body check tags ::