They will miss the Champions League group clash at Bayern Munich on Nov. 4 plus Premier League games at home to Tottenham Hotspur on Nov. 8 and Saturday's trip to Swansea City.
The pair were injured early in Tuesday's 3-0 League Cup fourth-round loss at Sheffield Wednesday after Walcott replaced Oxlade-Chamberlain only to also suffer a muscular injury.
"They are out but the scans are today -- it's 48 hours afterwards. We hope they are light injuries, but they are out until after the international break," Wenger said.
They will miss England's friendlies in Spain on Nov. 13 and at home to France four days later but Wenger hopes they will be back to face West Bromwich Albion after the international break.
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Oxlade-Chamberlain has a hamstring problem and Walcott is suffering with a calf injury, Wenger said.
Turning to injured midfielders Aaron Ramsey and Mikel Arteta and goalkeeper David Ospina, Wenger added: "It's the same for them. You plan for them all after the international break."
Asked about his right-sided options at Swansea, he said: "(Joel) Campbell and Alex Iwobi. Santi (Cazorla) can play there as well but he has become very important centrally.
"The problem sometimes is you can destroy two departments if you move one player out. We control the ball better with Santi in the middle," Wenger was quoted as saying on the club's official website (www.arsenal.com)
(Writing by Ken Ferris; Editing by Neville Dalton)
