is set to miss Manchester United
's FA Cup quarter-final at Wolves with a foot injury.
Lukaku's absence would be another blow for Ole Gunnar Solskjaer who is already without three forwards - Alexis Sanchez
, Jesse Lingard and Juan Mata - for the game at Molineux on Saturday night.
Lukaku is understood to have sustained the injury in the Champions League
win over Paris-Saint Germain and aggravated it in last week's defeat at Arsenal.
The 25-year-old striker has been having treatment at Carrington all week but is unlikely to play.
He will report for international duty with Belgium on Sunday and undergo further scans, but is already considered a doubt for the games against Russia and Cyprus.
Lukaku has been in excellent form, scoring six goals in three matches against Crystal Palace, Southampton and PSG before drawing a blank at the Emirates last week.
The £75million striker has also been shedding some muscle weight, and MailOnline revealed that he has switched his pre-match meal to ham and cheese omelette from a heavier pasta dish.
Lukaku's injury also comes at a time when United's injury problems appeared to be easing. Nemanja Matic and Anthony Martial returned at Arsenal, and Ander Herrera is expected to be available against Wolves following a hamstring injury.
Lingard and Mata should be fit again after the international break, while Sanchez is set to be out until next month.
If Lukaku is ruled out against Wolves, Solskjaer is likely to play a 4-4-2 formation again with Martial up front alongside Marcus Rashford.