كتب : Sherif Tarek
The 19-year-old dislocated his right shoulder during a pre-match training session on Tuesday, and was hospitalized shortly after.
"During Tuesday's training session, Theo Walcott dislocated his right shoulder after falling on the pitch," said an FA statement.
"Arsenal's medical staff were advised of the injury soon after the incident."
Walcott has just recently returned to action after injuring the same shoulder against Stoke City in the 2-1 Premiership defeat earlier in the month.
Moreover, the skilful winger has undergone surgery last year to fix his left shoulder.
England Coach Fabio Capello is now facing a tough situation, given that eight of his initial starting line-up have been ruled out with different injuries.
"We're all very disappointed, but the most important thing is for Theo to travel home and make a quick recovery," the former Real Madrid coach said.
Walcott is due to return home from Germany once the medical staff gives him the all-clear to travel back to London.