Doha — Romelu Lukaku will not play for Belgium at the World Cup until at least their final Group F match against Croatia, a team source told AFP on Sunday.
The forward did not take part in the Red Devils' first proper training session since they arrived in Qatar on Friday, as he continues his recovery from a hamstring injury.
Lukaku is Belgium's all-time top scorer with 68 goals in 102 appearances and was called up to their World Cup squad despite coach Roberto Martinez admitting he was not fully fit.
"It would be better for us if he was there for the first game (against Canada on Wednesday), but I cannot tell you when he will be back," Atletico Madrid midfielder Axel Witsel told reporters.
"The most important thing is how he feels. I was in his place in the last European Championship when I came back from an injury and I'm sure we'll have Romelu back very soon."
Lukaku has endured a difficult past 18 months, moving back to Inter Milan on loan after a dismal season with Chelsea.
However, the 29-year-old has played just twice for Inter since August after first picking up the injury in a 3-1 defeat at Lazio.
He returned to action in style last month, scoring in a 4-0 win against Viktoria Plzen that ensured Inter's passage to the last 16 of the Champions League but he then injured his hamstring again a few days later.
Martinez has to decide who will replace Lukaku up front for the clash with Canada. Fenerbahce forward Michy Batshuayi started in Belgium's one warm-up match before the tournament, a 2-1 defeat to Egypt on Friday.
Batshuayi was replaced by Lens forward Lois Openda, who pulled a goal back in the 76th minute of the clash in Kuwait City.
Belgium also take on Morocco before meeting 2018 World Cup finalists Croatia at the start of next month as they try to improve on their run to the semi-finals four years ago.
Martinez's team have long been dubbed the country's "Golden Generation" but with several among the Spaniard's core group either in or nearing their 30s, Qatar could be their last chance to be crowned world champions.
"For a group of players in the team this will be the last one, that's why we really want to give everything we have," said Witsel, 33.
"We have more experience (than in 2018), but time will tell in this competition.
"We went on a extraordinary run in 2018 as we were individually and collectively on top form, and we want to reproduce that here."