The Arsenal defender has been sidelined with a hamstring strain, while the team captain is still struggling with a groin problem
Coach Marc Wilmots confirmed on the eve of the last-16 encounter that while Vermaelen is recovering well from a hamstring strain, the game in Salvador has come too soon for the versatile defender.
"The situation with Thomas is that he will not be able to play but there's a high chance he'll be back for the last eight, if we make it," the former Schalke attacking midfielder told reporters at Arena Fonte Nova.
"He's already running and training fully with the rest of the squad, but he'll have to wait for us to reach the last eight."
Wilmots, though, was unable to speak with as much certainty when it came to evaluating the fitness of captain Kompany, who is still struggling with a groin problem.
"We don't know if he'll be ready for USA," the 45-year-old coach confessed. "He'll be training with us for an hour and a half [on Monday evening] at the stadium and we'll see how he is after that.
"But then we'll wait until the morning before taking a decision."
Meanwhile, Wilmots insisted that Eden Hazard, who assisted two of Belgium's three game-winning goals in the group stage, has not been affected by the criticism he has received for allegedly sub-par showings in Brazil.
"We are always talking about Eden," he lamented. "You are asking about someone who has already given a lot to us.
"We have evolved with four attackers so it's up to me to pick the proper strategy, to pick the right players. But Eden, he's the only one who doesn't suffer from pressure.
"It's true. He's very quiet. He enjoys the game. I could never manage to get cross with him because he's such a nice guy.
"He's someone who has very great ambition. But I don't want him to be on the only one with pressure on him. Individuals only shine when the team is good."
Wilmots also insisted that he and his players have not been perturbed by the fact that they have been criticised by their national press for their performances in Brazil so far - despite being one of only four teams to have emerged from the group stage with a 100 per cent record.
"This is the first time in our lives that we got nine out of nine [points], creating five or six opportunities per match," he argued.
"Perhaps we can still go up another notch but we are on schedule. I know that if we play one good match, everyone will be praising us.
"But I see things differently anyway: we've been working for two years now and we now have a good core.
"There's always praise for our opponents but we are doing well. We know our system, we know what we want to do and we know what we're going to do.
"We allow people to complain. As long as this team does everything it can to win, we will never regret anything.
"Everyone is free to have an opinion but we know what we're doing and where we're going."