Centre-back Ramos, 34, is out of contract at the end of the season.
The Spain international has won four Champions League, four Club World Cup and five La Liga titles in 16 years at the Bernabeu since arriving from Sevilla in 2005.
I want to be honest and I have to say I don’t know what’s going to happen with him,
We want him to stay here, He’s always going to be an important player and I want him to remain here, that’s what I’ll say as a coach.
Ramos, who has scored 100 goals in 668 appearances for Real, has said he wants to stay.
Zidane, meanwhile, would not discuss rumours linking Cristiano Ronaldo with a return to Real – who are eight points behind La Liga leaders Atletico Madrid – after Juventus were knocked out of the Champions League by Porto.
Everyone knows what Cristiano is to Madrid, what he’s achieved here, what we think about him and everything he did here was magnificent,
But right now he’s a Juventus player and I can’t say more than that. A lot of things have been said but we need to be respectful, Zidane said.