SAO PAULO (AP) -- Romelu Lukaku is nursing an ankle strain and will have to rest for up to four days, giving Belgium worries that it might have to start the World Cup without its main striker fully fit.
Lukaku sustained the injury during Belgium's 1-0 win over Tunisia and the federation released a picture Sunday with his right ankle heavily bandaged.
The problem is especially worrisome since Belgium has already lost its top-rated striker Christian Benteke to an Achilles injury he sustained two months ago.
Lukaku had been in great form, scoring three goals in a 5-1 win over Luxembourg and adding another in a 2-0 away win against Sweden over the past two weeks.
Belgium opens its Group H campaign against Algeria and also plays South Korea and Russia.