Arsenal manager Arsene Wenger says rotation was the reason why Per Mertesacker did not feature against Bournemouth last week.
The German came under heavy fire after getting sent off against Chelsea, paving the way for the Blues to cause a major upset at the Emirates.
But the Frenchman was full of praise for the 31-year-old ahead of tomorrow's key game at home against Leicester City.
"It's difficult for me to go into any individual assessment," Wenger explained.
"I think he has played many games. Sometimes I use a different formula.
"Per Mertesacker is a great leader, a very respected one in our dressing room, but I have three entire backs and I adapt a little bit to their level of form, to the number of games they've played and to the opponents we play against. What are their strengths and where can they hurt us?
"[Worried about Olivier Giroud's lack of goals?] Not so much because on Sunday he gave the ball to Mesut Ozil on the first goal.
"An assist or goal is, for me, exactly the same for a striker."