Belgium goalkeeper Thibaut Courtois has withdrawn from the squad for their opening two World Cup qualifiers this month because of a back injury.
The player's club Real Madrid said on Sunday that he had been diagnosed with sacroiliitis – inflammation of one or both sacroiliac joints in the area where the lower back and pelvis meet.
"The medical staff of Real Madrid and the Royal Belgian Football Association have discussed Thibaut Courtois' back problems intensively in the past period,” the Belgian association added in a statement.
"Both medical staffs have come to the conclusion that the goalkeeper is not fit for the upcoming internationals.”
The injury may also jeopardise Courtois' chances of playing at the Club World Cup in the United States, where Real Madrid open their campaign in Miami on 18 June against Al Hilal from Saudi Arabia.
Uncapped Nordin Jackers from Club Brugge will replace Courtois in the Belgian squad for the matches against North Macedonia in Skopje on Friday and at home to Wales next Monday.
Nottingham Forest goalkeeper Matz Sels is expected to take Courtois' place in goal for the two Group J fixtures.