Should Walcott's injury prove serious, it could force manager Arsene Wenger into the transfer market to bolster the depleted attacking options of the Barclays Premier League leaders, with forward Nicklas Bendtner set for a month on the sidelines because of an ankle problem.
"For Bendtner, it will be for one month, we expected it could have been more, but we had good news," said Wenger.
"With Theo, he has a knee problem.
"We don't know if it is a stretched ligament or just a kick, he got two kicks onto his knee.
"Of course if we lose Theo for a longer period, it is a problem."
The Gunners boss added: "I am waiting to see now who walks out there and knocks at the door, waiting to come in, but honestly, do we find better than the players that we have got?"
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