His team face the Championship high-flyers in the Scottish Cup’s third round with Luke Holt likely to deputise again for Mutch.
The 24-year old was on a development loan at Dalbeattie Star, playing in the Lowland League, but was recalled to cover after Mutch was injured in training.
Paddy Martin has pushed himself to be first-choice goalkeeper over the past month.
Sheerin said: “Robbie is out at the moment with a routine goalkeeping injury and he is improving every day and should be back soon enough.
“We are hoping he won’t be out for too long, but we had to recall Luke to cover until Robbie is available again, which is frustrating as he was getting games on loan. Outwith that, we should have a full squad to select from again.”