"You could feel that when he came off we were all very much anxious", Martinez said.More news: Sofia Richie reportedly broke up with Scott Disick for cheating
Coach Fernando Santos too wants his star man to enjoy his rest period before getting down to business in the World Cup, where Portugal have been drawn alongside Spain, Morocco and Iran.
Martínez also named Los Angeles FC defender Laurent Ciman as a reserve in case Kompany's injury proves too serious for him to play in Russian Federation.
"Vincent Kompany is a leader", he said. "His leadership is essential for us".More news: Novak Djokovic takes swipe at French Open officials
Martinez noted initial scans of previous Kompany injuries had not necessarily provided a true picture, and that "something that could be shorter is a lot longer, and could be the other way round".
Cape Town - Roberto Martinez has named a star-studded 23-man Belgium squad ahead of the 2018 Soccer World Cup in Russian Federation with defender Vincent Kompany included despite suffering a groin injury.More news: Samuel Umtiti agrees new five-year deal with Barcelona
"We feel a little bit disappointed for him because he's been working so well in the camp", Martinez said. "His performance against Portugal showed he's in a good moment. But we wanted to take two No. 9s for the balance of the squad".