Liverpool midfielder Emre Can is a doubt for this weekend's trip to Crystal Palace.
The Germany international was called up by his country for friendlies against Spain and Brazil but was released early because of a back problem sustained early in the win over Watford on March 17.
Can is still being assessed by Liverpool but did not take part in the first training session of the full squad at Melwood following all players' return from national team duty.
However, left-back Andrew Robertson, who was forced off with a suspected dead leg in Scotland's friendly with Hungary, was pictured training with the squad on Thursday.
Fellow defender Joe Gomez will miss the trip to Selhurst Park due to an ankle injury he sustained early in England's friendly win over Holland last Friday.