Portuguese outlet Record are reporting that Silva has been suffering from pain in his leg, and has not trained with the rest of the squad. He also did not travel with the team to Belgium for their match on Saturday, instead staying back to receive treatment.
Further information about Silva's injury isn't provided by the report, but there is clear concern that this injury may keep Silva out of the World Cup, as the report goes on to suggest that he may even have to be replaced.
Silva will be evaluated by the team once again when they return from Belgium, when a decision will be made as to whether he will be available for the tournament.
For Silva, it is a challenging end to what has already been an incredibly difficult season. Leicester agreed a deal of around £22m to sign Silva from Sporting in August 2017, but encountered a major problem when they attempted to officially complete the signing.
FIFA claim they received the documents for his transfer 14 seconds after the deadline, meaning he could not be registered as a Leicester City player until the next window opened in January. He was forced to sit on the sidelines for around 4 months until he was finally cleared to play.
His transfer is also subject to debate at Sporting, with a disagreement between the club and Gestifute, which is the agency owned by super agent Jorge Mendes, who represents the likes of Cristiano Ronaldo, David de Gea and Jose Mourinho. The two parties are disputing the amount which is owed to the agents, and could result in Silva being called into court to resolve the situation.
Portugal kick off their World Cup tournament with a tough match against Spain, before meeting Morocco and Iran. Silva will be doing everything in his power to recover from this injury before the first match on June 15th.