Kompany's participation in the World Cup was put in doubt when he suffered a groin injury in his country's 0-0 friendly draw with Portugal at the start of June.
However, the centre-back could yet be back for the clash with Gareth Southgate's squad, which takes place in Kaliningrad on June 28.
"Kompany might be available for the third game," Martinez told the media.
Thomas Vermaelen will also miss Belgium's tournament opener with Panama in Sochi on Monday, Martinez confirmed, though the experienced Barcelona defender is expected to be available for the rest of the group stage.
"Vermaelen can be medically fit for the following games [after Panama]. He is not with us here in Sochi and is working in Moscow," the former Everton manager added.
@LaurentCiman23 left the group this morning. Laurent returned to 🇧🇪 and will now remain one of our stand-by players, until Sunday evening 5pm. R. Martínez thanks him for his professionalism and contribution to the team during our #WorldCup preparation. #REDTOGETHER— Belgian Red Devils (@BelRedDevils) June 16, 2018
Belgium announced defender Laurent Ciman - who had travelled with his compatriots to Russia as cover for the injured Kompany - left the squad on Saturday.