Real Madrid have confirmed James Rodriguez has suffered a calf injury.
The Colombia international had tests on Monday, which confirmed muscle damage in his right leg.
It is unclear how long James will be out, but he is likely to miss the trip to Villarreal on September 1 and could sit out the international break, with Colombia playing Brazil and Venezuela in friendly matches next month.
James' injury is a blow to Zidane, who is already without Eden Hazard and Marco Asensio.
It had looked like James would leave the club during the transfer window but reported interest from Atletico Madrid and Napoli failed to materialise in a deal.
The 28-year-old is now expected to stay at Madrid beyond the transfer deadline of September 2.
"James has been in good shape and I would be happy if he stayed with us," Zidane said at the weekend.
James Rodríguez medical report. #RealMadrid— Real Madrid C.F. 🇬🇧🇺🇸 (@realmadriden) August 26, 2019