Gary Cahill sat out England training on Friday morning with an ankle complaint, although the injury is not expected to rule him out of the European Championship qualifier in Switzerland.
The 28-year-old started this week's unconvincing international friendly 1-0 win against Norway, playing 84 minutes before being replaced by Phil Jagielka.
Cahill was pictured with ice on his ankle after being substituted at half-full Wembley, but Three Lions boss Roy Hodgson quickly downplayed fears over his fitness.
The Chelsea defender did not train on Friday at St George's Park as a precaution, although he is expected to return to training on Saturday before playing in the match against Switzerland.
Cahill's absence meant only 19 of the initial 22-man squad were in action, given West Brom goalkeeper Ben Foster and uncapped Newcastle midfielder Jack Colback had already withdrawn through injury.
As a result, three members of the England Under-20s squad were drafted in to help with the training session.
Southampton midfielder Harrison Reed, Barnsley's Paul Digby and Exeter goalkeeper Christy Pym all started the session with Hodgson's side ahead of the Under-20s' match against Romania in Telford later in the day.