Midfielder Lee Bowyer has held talks with Birmingham, defender Calum Davenport has received an offer from Bolton and forward Luis Boa Morte is reportedly a target for Hull.
"We are trying to create a situation where everybody is happy. I said from the first day, this team has a big squad when everyone is fit," said Zola.
"I don't want to have players who train and are not playing. I want to have a situation where everyone can get a game, so some players might have to go."
He added: "(Davenport) has had an offer from a club. Now it is down to him to decide whether it is good enough.
"Lee Bowyer spoke to a club and we will see. He is not playing enough in this club and he may want to go and play some more football. We will see what happens. If he decides to stay we will be very happy to keep him."