The Manchester United striker has had positive results from tests on an ankle injury this week but is yet to return to full training with the squad.
And with Belgium sitting top of Group H and already assured of their World Cup place in Russia next summer, Martinez sees no point in risking him.
The former Everton boss is hopeful Lukaku can return for Belgium’s clash with Cyprus on Tuesday.
“At the moment, Romelu is working separately,” Martinez told reporters.
“He has not joined the group yet since he arrived. We need to be a little bit patient.
“I would say he is very uncertain for Saturday. We will make a decision probably on Friday, but I would say that it is a little bit difficult for him to be involved on Saturday.
“But we are still hopeful he will be involved on Tuesday [against Cyprus].
“He wants to play. He came with a little bit of a sore ankle. It is important that he gets that fully recovered. It is a period of the season that is really busy.
“We will give it as long as we can to make the final call but he is very uncertain for Saturday.”
United boss Jose Mourinho will be pleased with Martinez taking caution over his star striker with the Red Devils due to take on Liverpool after the international break.
Mourinho can’t afford to be without Lukaku, who has netted 11 goals in all competitions for United this term, with Zlatan Ibrahimovic also on the sidelines though injury.