Forward David Templeton has seen his return to action from the ankle injury he sustained during the draw with Annan in September delayed.
The 23-year-old has picked up a hamstring knock in training, with the former Hearts star already ruled out of the Gers' Irn-Bru Third Division clash at home to Peterhead this weekend.
While Templeton could return sooner rather than later, the news is less than encouraging for Fran Sandaza, Sebastien Faure and Anestis Argyriou.
The Ibrox boss said: "We seem to have a bit of a jinx on the boys that have signed for us. They have not had much luck in terms of injuries."
Sandaza is still recovering from a serious facial injury after a nasty clash of heads in the Light Blues' Scottish Communities League Cup win over Motherwell while Faure went under the knife yesterday in a bid to cure a groin problem that has kept him out of action recently.
Argyriou seemed likely to face the longest spell on the sidelines after he was stretchered off during the 7-0 Scottish Cup win over Alloa.
It was initially feared that the Greek defender could have suffered Achilles damage after going down unchallenged at Ibrox but it appears as though he has injured ankle ligaments, a problem that is still likely to keep him out for several weeks.
The latest injury news will come as a huge frustration to McCoist, who already has a small squad to work with as he attempts to lead the Gers to the Third Division title, although Lee Wallace and Emilson Cribari should be fit in the near future.
McCoist added: "Sandaza is out long-term, Templeton has been out for two months, Seb Faure has had an operation [yesterday] and Argyriou looks as though he will be out for a couple of weeks.
"The good thing is Lee Wallace is coming along nicely and we are hopeful that Emilson Cribari, who came off in the Alloa game, will be available for the weekend too.
"Templeton won't play this weekend. The ankle is fine but he is struggling with a hamstring injury.
"During his rehab he tweaked a hamstring so that's put a dampener on things.
"I don't think Argyriou is as bad as was initially feared. He has certainly damaged ankle ligaments and we will monitor this week and that will give us an indication of how long it will be, but hopefully not as long as we first feared.
"Sebastien had an operation [yesterday] and he will be five weeks after that. So it never rains but it pours but we will get on with it."