Morgan Gibbs-White and Keane Lewis-Potter have withdrawn from the England Under-21 squad to face Italy and Germany.
Nottingham Forest midfielder Gibbs-White and Brentford forward Lewis-Potter will remain with their clubs for assessment and treatment.
Their recordings mean Tyler Morton was first summoned by boss Lee Carsley.
The Liverpool midfielder, who is loaned to Blackburn, has three caps for the Under-20s.
The Young Lions are preparing for friendlies against Italy in Pescara on Thursday and Germany in Sheffield next Tuesday.