Ross County defender Tom Grivosti faces up to two months out after being hit with another injury blow.
Grivosti suffered a hamstring problem not long after scoring in Saturday's 3-1 defeat by Kilmarnock.
The 21-year-old only returned from a year out with a toe issue last month.
Manager Stuart Kettlewell said: "We are probably sitting with eight or nine guys that are injured. We pick up three more at the weekend on top of five or six who were missing on Saturday.
"One is definitely out and the other two are touch and go. Tom Grivosti is definitely out, we are looking at a tear of his hamstring, so that looks as if it could be maybe six to eight weeks, which I am gutted about.
"The other two were heavy knocks. Jordan Tillson came off and Regan Charles-Cook was limping pretty badly after the game, and still is."
Kettlewell declared Saturday's Scottish Premiership defeat as one of the worst in his 12 years in Dingwall after County struggled against a Killie team who played with 10 men for 82 minutes.
And he has given his players a clear challenge ahead of Sunday's Betfred Cup clash at Celtic Park.
Kettlewell said: "We speak about how hard the world is just now, people are paying to watch games pay-per-view, people are desperate to see their football team, and I didn't believe we got an application.
"I don't think we had a hunger and energy about us that befits the situation that we sit in just now.
"I went over the game with the players, we looked at the video, and I told them straight what I thought about it. I have not had one voice pipe up to say I'm wrong. Myself and the staff felt let down.
"But you get up again the next morning and look forward to how you can rectify it, and put aspects in play this week that challenge them and get then back on the front foot again.
"Anybody that doesn't show a desire to do that simply can't be a part of it. That's the stage I am at, I can't keep backing people if I can't trust what they are going to put out on a Saturday. That's the harsh reality of where we are.
"I probably need to strip it back and make it as simple as I possibly can for the players over the week, and that is just for them to show they have a real desire to play for this football club.
"It's a tough game but a very good game to look forward to, and I think it's a great platform to show people you should be playing at this level."
