The 31-year-old has picked up a serious ankle injury that is expected to rule him out for around 12 weeks, but manager Billy Dearden believes it could be longer.
The player picked up the injury during a recent clash with Luton, with it initially feared he had broken his ankle.
However, it has turned out to be more serious - with the player rupturing ligaments in his ankle.
It was not until Monday that the true extent of the injury was diagnosed.
Dearden said: "Ian came to the ground yesterday morning and was very upbeat.
"He said the ankle was feeling a lot better and was confident that it would not be too long before he was back - as were the rest of us.
"But then, at lunchtime, the results of his scan arrived and we had an unwanted shock.
"Ian has ruptured three of the ligaments in his ankle and is likely to be out for two to three months, but probably nearer three.
"With ligaments you never know exactly how long it will take or if there are going to be problems later on."
Dearden admitted it is a cruel blow, adding: "He had been outstanding on the left side of midfield, he has played a key role for us.
"You never like to lose any player but, given the size of our squad, he was especially valuable.
"In Ian we are losing somebody who can operate in four or five different positions."
