Morsy, who was forced to leave the field during last Saturday's game at Bristol Rovers, was due to have a scan on his injured knee on Wednesday.
Physio Jamie Hewitt said: "It looks like a medial ligament injury so at the minute he's on crutches and quite sore. The scan will determine how long Sammy will be out."
On a more positive note, Nathan Smith and Drew Talbot are both training and making good progress after being out injured. Hewitt explained: "Nathan has been training for the last couple of weeks now, just getting up to speed and fitness, so he's hoping to be pushing for a place in the squad soon.
"Drew had an injection in his groin area to calm down an injury that had been flaring up for a while. He had the injection last week and everything looked okay after he trained with the rest of the lads on Tuesday."