Ferguson travelled to England on Monday to meet a specialist to assess the injury which has troubled him for several weeks now.
However, McCoist believes the midfielder should be fit for the Hibs clash at Ibrox on Saturday.
"He has bruising on the bone, but it is not something thankfully which has stopped him playing.
"Once he sees the specialist we will know, but it is just a case of keeping on top of it and I'd certainly be hopeful he'd be involved at the weekend.
"In the long-term we are not concerned. It is something he has had for many, many weeks and we have been trying to rest him and look after him.
"We are hopeful he will be fit for the weekend and I'd be very surprised if this affected him in terms of playing," added McCoist.