Chilwell had to be substituted after 38 minutes in Leuven and left the pitch holding his lower back.
Chelsea manager Frank Lampard will be concerned Chilwell may not be fit for Saturday’s trip Newcastle when the Blues return to Premier League action after the international break.
Chilwell has settled seamlessly into the Chelsea side following his £45million move from Leicester over the summer and sorted the problem left-back position at Stamford Bridge.
At a time when Lampard just looks to have found a settled defence and goalkeeper including Chilwell, Thiago Silva and Edouard Mendy, losing Chilwell would be a blow for Chelsea.
Chilwell has been a key part of the Chelsea backline that kept five clean sheets in a row and went over 450 minutes without conceding a goal before their 4-1 win over Sheffield United.
The 23-year-old, who was making his first England appearance in a year, was replaced by Arsenal’s Bukayo Saka in Belgium.