Alex-Oxlade Chamberlain was forced off the field less than five minutes into Arsenal's Capital One Cup clash with Sheffield Wednesday on Tuesday.
The 22-year-old, playing in a forward three with Alex Iwobi and Joel Campbell behind Olivier Giroud, had possession of the ball just once in the opening exchanges before pulling up.
Theo Walcott was summoned from the bench by manager Arsene Wenger as Oxlade-Chamberlain hobbled down tunnel with a reported tightness in his hamstring.
Sky Sports later said Arsenal's decision to cut short the England international's evening was 'precautionary' but the Gunners forward, who has been handed just three Premier League starts so far this season, will be frustrated to miss the chance to stake a claim for more league starts.
Walcott was brought on and assumed position behind Giroud, who was chosen ahead of his Arsenal team-mate to lead the line for the second successive match. But the Gunners forward - who was denied the opportunity to warm up as Wenger rushed him on to replace Oxlade-Chamberlain - was soon down nursing an injury of his own.
And, inside 20 minutes, the Arsenal boss was forced into his second substitution of the evening as Walcott, who started the night on the bench, came off with a calf problem.
Running out of options, Wenger called on 17-year-old Frenchman Ismael Bennacer to make his Arsenal debut.
