The summer signing from Accrington suffered the problem in the 2-2 draw at Walsall two weeks' ago, and a follow-up scan on Friday has shown a worse prognosis than initially thought.
"It is looking like months rather than weeks, he has quite a bad tear at the base of his medial ligament and it's looking like a fairly long lay-off," Iron manager Alan Knill told the cub's official website.
"I am hoping he is going to be back before the specialist have said."
Cliff Byrne, the club captain, was also due to see a specialist on Monday on his ongoing back problem which has kept him out of action since January.
There was some better news on the injury front, as Mark Duffy returned to training following a knee injury.