The City boss revealed that the late victory over West Bromwich Albion last weekend took its toll on his side, enforcing changes in personnel.
He told Sky Sports News: "We spent a lot of energy on Saturday, playing for 70 minutes with 10 men so we need some fresh players tonight.
"We could have a chance at set pieces. Pablo Zabaleta is not fit, he played two games for Argentina but he should be fit for the weekend. Ajax have a young team and play football very well but it is important we take three points."
Ajax and City are both chasing their first victory in this season's Champions League in a group also featuring European giants Real Madrid and Borussia Dortmund.