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The Germany internationals all played key roles as Joachim Low’s side triumphed in Brazil, beating Argentina 1-0 in the final on July 13.
The Gunners open their Premier League campaign on August 16 against Crystal Palace but Wenger does not see the trio being available for selection.
"I have given them a good break because I have experience of players who have been in the World Cup final. You need a rest," the Frenchman told reporters. "Will they be ready? Mertesacker prepares well - but for the first game ... I don't think they will be ready for August 16.
"A post-World Cup year is always very difficult and short. The World Cup final was July 13 and the start of the Premier League is August 16. From FIFA we are obliged to give four weeks' holiday to the players so I don't know how all that works together. It looks impossible to me.
"A post-World Cup year is always very difficult for every big club because the players have been away."
Wenger is hopeful that the Gunners, currently in the United States on their preseason tour, can add more silverware next season after having their long trophy drought ended by claiming FA Cup glory last campaign.
"We always have high expectations but we haven't always fulfilled them," he conceded. "We are very ambitious and last season we went 128 days at the top of the Premier League but were left frustrated because we couldn't win it.
"Overall, we were very consistent, we won the FA Cup and we want to win more next season but the level of competition is very high and it's very difficult to predict how much better other teams will be. We just have to ensure we have good preparation and hopefully we will have a good chance to win the title."