The England camp say Tottenham defender Ledley King's fitness is a day-to-day proposition.
King suffered a groin injury in Saturday's draw with the United States in Rustenburg and was immediately ruled out of Friday's second Group C encounter against Algeria in Cape Town.
However, it is thought the damage is more serious than that and with a recovery period of three weeks hinted at, the fear is that King will play no further part in the competition.
The 29-year-old was at training on Monday morning but spent only the briefest time on the pitch when Fabio Capello delivered a short address to the squad.
He then made his way to the pool to continue his rehabilitation work.
"Ledley has a groin muscle strain. He will be assessed on a day-to-day basis," said a Football Association spokesman.