The Southampton defender has been ruled out of tomorrow's game at the Banks's Stadium having been examined after training with Stuart Pearce's Young Lions this morning.
Shaw will now return to the south coast to be assessed ahead of this Saturday's game against Barclays Premier League champions Manchester City.
This was the 17-year-old's first involvement with the Under-21 squad having previously been capped at U16 and U17 level before breaking into Saints' First Team, but he will now be forced to wait for his U21 bow.