But Glenn Roeder is hoping the 27-year-old winger will be able to delay the operation.
Roeder: "Damien is going to see a knee specialist in London tomorrow. He has already seen the scans of his knee and he will decide tomorrow whether he needs to have a small operation or not not.
"If he decides to operate, it would be to remove a small part of his cartilage which has been damaged.
"Sometimes you operate in these situations and sometimes you put it off until another time."