Kevin De Bruyne may miss Belgium's opening game of the Nations League on Saturday with his wife set to give birth to their third child, team officials said on Wednesday.
De Bruyne did not join up with the rest of the squad when they assembled in Belgium on Tuesday to prepare for matches against Denmark in Copenhagen on Saturday and then Iceland in Brussels next Tuesday.
De Bruyne has permission to stay with his family and his participation will depend on the birth, added a Belgian football association spokesman.
The squad have already been hit by the withdrawals of striker Divok Origi, goalkeeper Hendrik Van Crombrugge, defenders Dedryck Boyata and Elias Cobbaut and midfielder Nacer Chadli, who all reported injuries.
Defender Thomas Vermaelen was unable to travel from Japan because of Covid-19 pandemic restrictions.
Coach Roberto Martínez has only called up Ghent goalkeeper Davy Roef as cover.