Chelsea star Reece James is in danger is missing the World Cup in a huge blow to England boss Gareth Southgate - with his knee injury more serious than first thought.
Surgery could even be a possibility for the right-back - who was forced to come off during Chelsea's 2-0 win at AC Milan this week, being substituted for Cesar Azpilicueta in the 62nd minute at the San Siro.
James has started six of Chelsea eight Premier League games and his absence will be felt at both club and national level. Under Potter, James has played all four of his first games, while the 22-year-old started England's last game against Germany - grabbing an assist in the 3-3 draw last month.