The 25-year-old suffered the injury in the defeat to Millwall last weekend and manager Sean O'Driscoll has admitted that he will not return this year.
"The medical people are going to see how it settles down and decide whether he needs surgery or not," said O'Drsicoll. "Nobody wants an operation and if we can get a good prognosis that he will be okay then he won't have one.
"But we are hedging our bets. We don't want to get two months down the line and then find that he needs an operation."
Forest travel to Leicester City in the Championship on Saturday.