Newspaper reports have consistently suggested the Welshman could move to Old Trafford in the future, while Arsene Wenger's Gunners have also popped up as a potentially interested part in recent days.
The 28-year-old has not played since limping out of Madrid's 3-1 Champions League win over Borussia Dortmund at the end of September with a calf injury, with a strained adductor muscle in his left leg having further delayed his comeback.
Los Blancos host Malaga on Saturday and while the game will likely come too soon for Bale, Zidane hopes to be able to bring him back soon and reiterated he is important to the Liga giants.
"We know what Gareth can give us. He's a very strong player, technically good and works a lot," said Zidane.
"He's an important player for us and he knows that. The important thing is that we have to get him back into shape and ready to play.
"What he can give us is strength. He's fast; he can open things up for us and can give us a lot of things.
"I don't know when he is going to play. He hasn't had any trouble today, but we'll see when he can play.
Bale missed three months of the 2016-17 campaign with a serious ankle injury and Zidane was keen to point out that the former Tottenham star will be out for a shorter period this time.
He added: "I think it's going to take less time to get back – the injury this time will not be for such a long time.
"We're in the same situation – we need him back 100 per cent but I don't think it will be as long as last time.
"He's already back in training and he's in decent shape."