The England midfielder Alex Oxlade-Chamberlain says he is staying positive over his chances of playing in the football World Cup.
The FA has confirmed that the 20-year-old suffered a medial knee ligament injury in England's warm-up game with Ecuador.
England have put no time scale on his recovery and could name a replacement up until June 13th.
England open their World Cup campaign against Italy in Manaus on 14 June.
Reports suggest Oxlade-Chamberlain could be out of action for between 10 days and three weeks.