Captain Steven Gerrard was among three England players that did not take part in this morning's training session.
The Liverpool midfielder, Tottenham Hotspur full-back Kyle Walker and Manchester United's Ashley Young were instead believed to be undergoing their own regimes in the gym.
It has been said that all three had been advised to sit out today's session by medical staff, but none of trio is thought to be doubtful for Friday night's clash against San Marino.
A handful of players have already withdrawn from the squad because of fitness concerns, including Rio Ferdinand and Gary Cahill.
