Oxlade-Chamberlain has started five of his 10 league appearances for Liverpool so far and Wenger believes that the playmaker will have to fight to become a regular in Juergen Klopp's starting lineup.
"Is he sure of a place there? You are sure of a place nowhere," Wenger was quoted as saying by the Guardian.
"In a big club you have big competition with some good players. That is absolutely normal. What do you want to be, a big player and not have to fight?
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"You can't be a big player, sit in your rocking chair and say 'I do not want to fight'. It doesn't work like that. Every player has to fight."
The Frenchman said that he would have liked Oxlade-Chamberlain to extend his stay at Arsenal but said that he respected the midfielder's decision to leave and believes that he will establish himself in the England squad.
"At the start of the season we had four players with one year to go and I wanted him to extend his contract," Wenger said.
"Yes, he decided to go and we respect that. He made his decision and we had to find a compromise to get the best possible transfer fee.
"I personally think he will be an important player for England and that he will continue to develop."
Arsenal are a point and a place behind fourth-placed Liverpool and host their rivals at the Emirates later on Friday.
(Reporting by Aditi Prakash in Bengaluru; Editing by Toby Davis)
