The Portuguese superstar suffered an ankle injury in Sunday's 2-2 draw with Barcelona, resulting in him being substituted at half time.
"It is a Champions League final and we know what Liverpool can do".
The Portugal striker will miss tomorrow's La Liga clash against Sevilla.
Real Madrid holds a shining away record and are now riding a seven-game undefeated streak on the road, a sequence which has featured no fewer than six wins.
Zidane had labelled Ronaldo's latest injury as "small thing" and insists that he isn't anxious about the forward regaining full fitness for the final.
"Everyone will be available for the final, I'm telling you, 150 percent".
A win on Wednesday will move them level on points with second-place Atletico Madrid, with matches against Celta Vigo and Villarreal to come.
He said in quotes reported on www.realmadrid.com: "It is going to be an open, spectacular game, with both teams getting chances". They have a bit of everything: physicality, technique and speed.
"It is a sprain, but there is no particular damage on the fibula, it is a small sprain and his ankle is stable", Zidane said.
"What matters most for us is planning, showing up and making things hard for them".