Marcelo has been linked with Juve ahead of the January market.
Ronaldo told Gazzetta dello Sport: "I saw in the newspapers that you talked about several players for Juventus. Marcelo, Bale, James Rodriguez, Asensio ... But there are already great champions here. Juventus does not need other players.
"We have a quality squad, we have many options. We do not need anyone. Then, of course, you have to talk to the president. But I'm happy with how Juventus is currently.
"I do not know what will happen in the future and if Marcelo, since you told me about Marcelo, will arrive. He is strong, but I do not know. Anyway, we open the doors to all good players. Marcelo is one of them."