Everton manager Roberto Martinez admits the club still does not know how long Kevin Mirallas will spend on the sidelines.
The Belgian winger suffered a hamstring injury in the first half of the weekend's 1-1 Merseyside derby draw with Liverpool and could be out for some time.
But Martinez could not pinpoint exactly how much time Mirallas will miss as it has been difficult to truly assess the troubled area.
"At the moment it is still a bit early because the inflammation in the area doesn't allow us to get the full extent," said the Toffees boss ahead of Thursday night's Europa League clash with Kuban Krasnodar.
"But clearly it is an injury that will keep him out for a while.
"We are just going to make sure in the next 48 hours we get the clear diagnosis for it."
