Midfielder Oxlade-Chamberlain was forced off at half-time of the season-opening 3-1 home defeat to Aston Villa with what the club confirmed was a knee injury.
The Sunday Mirror says the 20-year-old was on crutches after the game, and there is a real worry he has suffered serious damage.
A spokesman for the Gunners said Oxlade-Chamberlain's injury was being assessed and it is too early to confirm how bad it is.
Ligament damage could keep the player out for three months, which would be crushing news for both Arsenal and England.
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