The Belgian international joined Madrid in 2019 but has been blighted by injuries, making just 25 La Liga appearances.
After returning from a muscle problem for the final 15 minutes in Saturday’s last-gasp 2-1 win over Elche, Zidane said Hazard will miss Tuesday’s Champions League home last-16 second leg with Atalanta.
“He won’t be fit. They’re things that I can’t explain. I want to be positive and hope that it’s not too much of a problem,” Zidane said.
Real said in a statement that Hazard is suffering from a psoas - the primary muscle connector between the body’s trunk and lower limbs - problem but gave no indication of a likely timescale of his absence.
“Something’s up, because he was never injured in his entire career (before joining Real) or there were very few injuries,” Zidane said.
“It’s something new. I can’t really give any more of an explanation. We want to help him and hope he’s back as soon as possible.
“We’re going to try and figure out why it’s happening (the club’s injuries), but right now we can’t explain it. We’ve spoken about things like the lack of pre-season, amount of games and the mental aspect.”
Hazard joins Casemiro on the sidelines for the fixture against the Italians, with the Brazilian suspended after picking up a booking in the first leg, however, captain Sergio Ramos is fit and likely to start.
Real won last month’s first leg 1-0 in Bergamo thanks to a late Ferland Mendy strike.
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