Zidane rested the player in Madrid's last match against Real Betis last weekend. However, now as per Madrid's official reports, the midfielder has missed training on Tuesday and now will miss Madrid's next League encounter against Leganes at Butarque having "been diagnosed with a muscle injury in the biceps femoris of the right leg."
"Modric has a hamstring issue," Zidane told a news conference. "I always have faith in the staff here, the physios and doctors, so he will be back with us quickly. I don't think it is serious."
Modric has joined the treatment table with two heavy names, midfielder Toni Kroos and left-back Marcelo who have also suffered injury issues within one week.
Kroos suffered a knee injury during Madrid's big victory against PSG last week whereas Marcelo had to be limped off the field during the Betis game midway.
Talking about the injury issues, Zidane was not able to address the return date of the players, though, he suggested that the massive encounter with PSG might have taken a toll on their body and he is hopeful that all three could for the next tie at Parc des Princes.
"I am always positive," he said. "I do not like to see today that we have three or four players out injured. I hope they are not out too long, but we will see. I hope it is short.
"It can be that, when there are certain [injury] problems, it's because of an enormous effort. But, at the same time, in order to cope with matches like the one against PSG, we have to repeat those efforts.
"We have to maintain the pressure in every game and to keep doing it for 90 minutes. And doing it every three days is positive. When you're winning playing every three days, you're more optimistic. That's what we need now."
With so many injury issues in the team, Zidane is likely to rotate his squad for the match against Leganes and players like Kovacic, Theo Hernandez could get a chance to feature in the match from the start.