Belgium coach Marc Wilmots had yet to reveal his final 23-man World Cup squad to the press on Tuesday, a day after FIFA`s final June 2 deadline.
All bar one position, that of the third-choice goalkeeper, was already known, and the media department of the Belgian Federation could not be contacted to provide confirmation.
Koen Casteels, of German Bundesliga club Hoffenheim, was expected to be included in the squad as the third-choice `keeper, but he is recovering from a fractured tibia and his fitness remains a concern.
Sammy Bossut of Zulte-Waregem has been standing by to take his place.
However, Belgian media reports say Casteels will make the squad, especially as FIFA regulations mean he could still be replaced before the World Cup begins if he does not recover fitness in time.
The rest of the Belgian squad will be that announced by Wilmots 10 days ago, with veteran Club Brugge midfielder Timmy Simons and Radja Nainggolan of Roma the most notable absentees, along with injured Aston Villa striker Christian Benteke.
Belgium World Cup squad (including uncertainty in goalkeeping position)
Goalkeepers: Thibaut Courtois (Atletico Madrid/ESP - on loan from Chelsea/ENG), Simon Mignolet (Liverpool/ENG), Koen Casteels (Hoffenheim/GER) or Sammy Bossut (Zulte-Waregem)
Defenders: Toby Alderweireld (Atletico Madrid/ESP), Anthony Vanden Borre (Anderlecht), Daniel Van Buyten (Bayern Munich/GER), Vincent Kompany (Manchester City/ENG), Jan Vertonghen (Tottenham Hotspur/ENG), Thomas Vermaelen (Arsenal/ENG), Nicolas Lombaerts (Zenit Saint Petersburg/RUS), Laurent Ciman (Standard Liège)
Midfielders: Axel Witsel (Zenit Saint Petersburg/RUS), Marouane Fellaini (Manchester United/ENG), Steven Defour (Porto/POR), Moussa Dembélé, Nacer Chadli (both Tottenham Hotspur/ENG), Kevin De Bruyne (Wolfsburg/GER)
Forwards: Romelu Lukaku (Everton/ENG - on loan from Chelsea/ENG), Divock Origi (Lille/FRA), Eden Hazard (Chelsea/ENG), Kevin Mirallas (Everton/ENG), Dries Mertens (Napoli/ITA), Adnan Januzaj (Manchester United/ENG)