Cvitanich, the joint second-highest scorer in Ligue 1, picked up the knock in the 2-0 win against Brest and it is now clear that the ligaments have not been damaged.
"[Cvitanich will be out for] two to three weeks," Nice's official website quotes Puel as saying.
"What is reassuring is that the ligaments are not damaged. It is unfortunate, of course."
Cvitanich could return for the clash with Reims on February 23, but is more likely to play again at the start of March.