Due to a left thigh injury, Lukaku, 29, hasn't played since Oct. 29 and hasn't completed a full 90-minute game since Aug. 13 in Inter Milan's Serie A debut against Lecce.
"We are thrilled with how he is developing. He had a great workout yesterday without a group, but he is improving steadily, according to Belgium coach Roberto Martnez on Tuesday. "We don't have a timetable.
I wouldn't be able to predict whether he would appear in the second or third game, the man said. "If I follow the medical advice, at this point it would be the third game. If I follow how the player feels, probably we've got a chance for the second game."
Despite having less playing time this year at Real Madrid, captain Eden Hazard will start. The 31-year-old has only made two starts: on September 11 in La Liga and on October 11 in the Champions League.
Regarding playing time, Martnez said, "It's been a difficult situation." We perform better as a team when Eden Hazard is present, without a doubt.