Lukaku only returned to training this week following Belgium’s World Cup campaign and will not feature in the club’s final warm-up match against Bundesliga side SC Paderborn today along with fellow countryman Kevin Mirallas.
Everton travel to newly promoted Leicester City next Saturday and manager Martinez admits the former Chelsea striker may not start the showdown.
“When you have players coming back from the World Cup you have to decide if you want the players straight away or do you give them a bit of time to refresh and be ready to play for 10 months?” said Martinez.
“It will only be Kevin Mirallas and Rom who might not start the season. For Romelu, it will depend on how he adapts to work from now until August 16.
“There is a degree of risk if you put them into a situation so early. They’ve been training really well and are accumulating a lot of work.
“Playing in a game would have stopped them being able to get in a lot of that extra work and we didn’t want to do that.
“They’re not going to be a part [of the team] but they will get three sessions in while we’re out here.
“That will accelerate the process of them being ready as quickly as possible.” Lukaku’s last football came when he played the final 31 minutes of Belgium’s quarter-final defeat by Argentina.