Celtic will have to deal without the services of midfielder Beram Kayal for up to a month.
The Israeli was stretchered off during the second half of Wednesday's 1-0 Old Firm win over Rangers following a 50/50 challenge with Lee McCulloch which damaged ankle ligaments.
Celtic released a statement on their official website saying that Kayal had undergone two sets of scans that indicate he will need to be sidelined for about four weeks although a re-examination will take place in a week.