Los Blancos ran out 5-2 winners over Real Sociedad, with Modric dropped to the bench and Bale playing only 17 minutes.
Ronaldo scored his first hattrick and played all 90 minutes, as Zidane removed Asensio and Vazquez instead.
“I know [the XI] , but we will see on Wednesday,” Zidane told reporters, after Unai Emery suggested he was unsure over the make-up of his PSG selection.
“Everyone is ready to play on Wednesday and I do not want to say who will come out.”
Of Madrid blitzing Sociedad by racing into a 4-0 lead before the interval, Zidane added: “The first half was phenomenal, we scored fast, we pushed, we put intensity in.
“Then we controlled the game and made the changes, thinking about the next game, but I’m happy.
“It makes things easy when you score in the first minute. It was the full first half in this way, intense, determined, motivated. It was a good way to prepare for Wednesday’s game.
“We have to correct certain things, especially in the second half, but I am left with the positive side, with the five goals and our start of the game. Wednesday will be another game and we will have to put in another effort.