"I rotate considering the level of fatigue," Wenger told a news conference.
"We have some indications - my eyes, some objective data and as well some positions where it's more demanding on the physical front than others.
"We have so many games that in some positions I will have to change; the full back position is one that is very demanding. Central defence is a little bit less demanding on the physical side, it's more on the concentration side.
"When you play so many games of that intensity, we expect to lose one or two players. In every single game I will rotate. I try to limit the number because I do not want to disrupt the balance of the team, so I do that in every single game."
With striker Olivier Giroud and midfielder Aaron Ramsey having scored 15 league goals between them this season, Wenger said he is not in a hurry to add to his forward options in the January transfer window.
"I am not concerned about that," he said.
"We have at the moment Yaya Sanogo who is a striker we brought in during the summer, who is coming back from injury. Hopefully, he will help us in the second part of the season."