The defender picked up the injury when playing for France in midweek and was given every chance to make Arsenal's clash against Sunderland at the Stadium of Light on Saturday.
However Koscielny failed a pre-match fitness test and Wenger decided not to risk him for fear of aggravating the problem further. It was a wise decision as Wenger says he will not be on the sidelines for long.
"It's a calf problem. We think it's a question of days [until he returns] because he had a positive scan," Wenger revealed. "He [came off for France] at half time [on Wednesday] and we decided to give him a trial in the warm up.
"He was not good enough. I don't think it's long-term."