Belgian head coach Marc Wilmots has admitted that Kompany, who missed the Red Devils' final group stage match on Thursday -- could only train for a half hour on Friday and is still day to day.
"It’s impossible to say this now,’ he said. "That is why I’m happy to have an extra day of recovery. Now we wait for the reaction, the training and the development day by day, but you saw the last game too – he tried hard in the last training session and had to stop after half an hour."
Kompany, who is also the captain of English Premier League champions Manchester City, has been a mainstay for the Belgian side for the better part of a decade. His absence from the lineup would certainly weaken the Belgian defense, and possibly present an opportunity for the US attack, especially if forward Jozy Altidore regains his health.
"It will be day by day and that is why I don’t think about the lineup now," Wilmots said. "We have to wait to see if he will be fit, certainly the day before the match, after the last training session. That is when we’ll have to decide."
In addition to Kompany, several others are either ruled out or questionable. Arsenal center back Thomas Vermaelen remains doubtful due to a hamstring strain, and spent Friday's practice session away from the squad and under the guidance of the trainers.