Injury-plagued striker Cresswell missed the Blades' second-leg win over Stevenage due to an eye infection, while midfielder McDonald was forced off at half-time due to a hamstring problem.
Boss Danny Wilson spared a thought for Cresswell, who has endured a catalogue of injuries this season, saying: "He's got an eye infection - unbelievable. He woke up in the morning and couldn't open his eye and then when he could open it he couldn't see a thing out of it.
"So we rushed him to the hospital and they put some drops in, but there was no chance he could play. We gave him as much time as we could, but he just couldn't see out of his eye.
"I felt sorry for Cressy because he's such a dedicated boy and is just desperate to play. He broke a bone in his arm, broke his nose, then did his shoulder and now he's got an eye infection. But it's nothing too serious and in 24 hours he'll be ok."
