"Everything had gone smoothly over the last month but we have two minor injuries," Wilmots told reporters at the Corinthians arena. "They are not very serious but we want to keep them fresh and they won't play against South Korea."
Vermaelen was expected to miss the match after being taken off early in Sunday's 1-0 win over Russia. Team captain Kompany, meanwhile, has suffered a flare up of an old groin strain.
"It is about the groin injury, he stopped training after 35 minutes and I think he has over exercised a bit," Wilmots said.
"It is early days yet. I don't think it is serious but we will wait until tomorrow. We will take our time, we have four or five days and we will follow our programme. We have two doctors who will take a look at it and we are going to take our time and analyse this."
Belgium have already qualified for the last 16 go into the match needing a point to guarantee first place in the group.
The team have a string of players who ply their trade at top European clubs. They impressed in the qualifiers, topping their group unbeaten, with a record of eight wins and two draws.
But while they have a 100 percent record in the tournament so far, they have struggled, needing late goals to bat both Russia and Algeria, whom they overcame 2-1 in their first match. Stars such as Eden Hazard and Romelu Lukaku have failed to reproduce their club form.
Wilmots was unconcerned at their inability to meet expectations and hinted he will give some fringe players a chance to show what they can do against a South Korea side that has never beaten them and needs a convincing win to have any chance of progressing.
"I have a very good core of players and I had a number of players who wanted to show what they can do, I could see it when they trained," Wilmots said.
"But there is a lot of competition. Now I have the opportunity to include fresh players, players who have not played for two or three weeks. Those who are coming to the pitch have a lot to prove, they can showcase what they can do and there will be a lot of competition on the pitch."
Wilmots said he was not content with just progressing beyond the group phase.
"This is a young team, we wanted to reach the knock out stage, this has been achieved and we won't settle for the round of 16," he said. "We want more than that."
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