Gedion Zelalem will be sidelined for up to nine months after tearing the cruciate ligament in his knee while playing for USA at the Under-20 World Cup in Korea.
The 20-year old Arsenal winger was taking part in the United States' clash with Ecuador before being forced off the ground after 34 minutes.
And according to reports from football.london, the extent of the injury could see Zelalem miss from six to nine months.
The talented midfielder has previously spent loan spells at Rangers and VVV-Venlo.