Reports in France claimed that Nasri could be out of the World Cup but his girlfriend Anara Atanas said the lay-off may be as short as four weeks.
Nasri's father told Le Parisien: "I've spoken to Samir on the phone. The disappointment has subsided a little. I tried to keep it inside, and he did as well.
"Samir will have an MRI on Monday. We'll then have a precise diagnosis. He's afraid of a long-term injury which will end his season and his dreams of the World Cup.
"But after taking a step back to think about it, and with certain signs, he thinks it might just be a severe twist. If the (cartilage) meniscus is damaged, he'll be out two months, which isn't enormous.
"In that case, it could have been much worse and he'll even be able to take a breather and recharge his batteries. He's trying to keep things in perspective."
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