Arsene Wenger feels the World Cup is to blame for Arsenal's injury troubles this season.
The Gunners have suffered injuries to 10 first-team players since August, with World Cup winner Mesut Ozil recently being sidelined for up to three months with a collateral ligament tear in his left knee.
France internationals Olivier Giroud and Mathieu Debuchy are also long-term absentees but Wenger is hopeful that his players will come back stronger following rehabilition.
"There are a lot of post-World Cup injuries and not many soft tissue injuries," Wenger told reporters.
"I gave [those who played at the World Cup] until August 11, Germany played the final on July 13, that was a month and should be enough after a big competition.
"For example, Giroud - I don't know what we can do about Giroud's injury. Debuchy was on his own when he did the ankle.
"Then you have Ozil. You know how Ozil did the injury? Passing the ball with the outside of his left foot. He must have done that a million times. He just wanted to give the ball like that and heard a little crack.
He added: "I think we have made progress. What's different is we have a bit more prevention than before for the players to prepare. For us this season, we had big injuries and coincidental injuries."
Koscielny has played the full 90 minutes in Arsenal's last six games, but Wenger admitted giving the centre-back a prolonged rest to overcome a niggle is a possibility.
"Koscielny has an Achilles problem, which has got worse. He finds it difficult to play with it at the moment. You can only trust what the players says, he does not feel ready to play and will not play on Saturday," he added.
"An inflammation of an Achilles tendon, if you wait for it to be better, it can be a short time. If you want to get rid of it completely, it is long term.
"We will monitor him and as soon as he can take enough pain again he will play. No [he will not need surgery]. We have scanned him, there is no deterioration of his achilles at all. It is just the inflammation