"Craig's ankle is very sore and swollen at the moment," boss Nigel Worthington told the club's official website.
"Without putting a definite time on it, we are looking at a few weeks. It is a twist just above the ankle but not a break.
"Of course it is disappointing to lose him, you have seen the way he has started off this year.
"The lad himself is absolutely gutted. Craig would have wanted to have keep things going like any player but that is just the way it goes."