Manager Arsene Wenger told Arsenal TV Online the loss of Sagna was "completely disruptive" and now it appears he will have to find cover at right-back until mid-April at best.
"He has an ankle injury and the first news that we have is that he could be out for quite a while," said Wenger.
"I don't know [exactly] how long he will be out but I feel it will be three weeks at least. Five is the [worst case scenario].
"I have seen the injury again on tape. He wanted to kick the ball out and he twisted his ankle. That made it a bad injury."