كتب : Megan Detrie
The 17-year-old striker collected the injury during Sunday's training session and added to the worries of coach Sven-Goran Eriksson about his attacking line.
With Michael Owen struggling to restore his touch following a long lay-off and no confirmation on Wayne Rooney's form, Eriksson wish to have Walcott ready for England's second game.
The Arsenal player, who has yet to make his Premiership debut, was on the bench during the 1-0 victory over Paraguay in Group B opening matches.
In May, Walcott became England's youngest player ever to play for the national team when he came onto the pitch as a substitute in a friendly against Hungary at Old Trafford.