Ledley King is being assessed by England's doctors on a day-to-day basis as he fights to recover from a groin injury that threatens his availability for the remaining World Cup group games.
The Tottenham centre back, who briefly emerged at training Monday before going off to the swimming pool for light training, was forced off at halftime of Saturday's 1-1 draw with the United States and is in doubt for the remaining group games against Algeria on Friday and Slovenia on June 23.
"Ledley has a groin muscle strain," the Football Association said. "He will be assessed on a day-to-day basis."
Tottenham manager Harry Redknapp, whose physiotherapist Wayne Diesel is in South Africa to help King's fitness regime, shed more light on the injury.
"I don't think we'll see Ledley again if he's struggling to play," Redknapp said Talk Sport radio. "They are getting the result back from the scan today, but if there's a tear in the groin that would make it difficult for him. That's the problem for him, when you don't train and have to play at that top, top-lass level you're going to pick up injuries."
King was brought into the starting lineup after captain Rio Ferdinand's tournament was ended by a left knee injury. Ferdinand's squad place was taken by Michael Dawson.
Jamie Carragher replaced King on Saturday, suggesting he is the leading candidate to replace King as John Terry's central defensive partner. However the 32-year-old Liverpool defender was beaten for pace by U.S. striker Jozy Altidore to create a goal-scoring opportunity Saturday, and the younger Dawson or Matthew Upson may be preferred.
Striker Wayne Rooney and defender Ashley Cole also skipped training Monday for light work in the swimming pool at England's Rustenburg base.
Rooney got a kick to an ankle on Saturday, while Cole usually requires an extra day's rest after matches as a legacy of past injuries. They are expected to be fit to face Algeria in Cape Town.
Opening the tournament with a draw has provoked a wave of criticism against Capello in the English media.
"I'm sure Fabio Capello will be fine. He's been manager of Real Madrid and AC Milan," Carragher said. "I know we talk about the pressure of managing England but speaking to some of the Spanish players I think Real Madrid is another topic altogether. I'm sure he'll be fine."