The Arsenal forward, 27, has been in fine form this season, bagging eight goals in 13 appearances.
Walcott missed the final training session ahead of tonight's Champions League clash against Paris-St Germain.
Wenger decided against risking Walcott from the off but he is fit enough to make the bench with Olivier Giroud taking his place in the starting XI.
"Walcott has a slight problem with his toe," Wenger said on BT Sport.
"I have plenty of players who are fresh and available and need games.
"So I try to rotate a little bit and keep the balance depending upon the opposition and that’s why I brought Giroud back in."
A win against PSG would guarantee Arsenal progress to the last 16 as Group A winners.
