Aberdeen boss Derek McInnes says "it is a real blow" that Greg Leigh and Craig Bryson face two months out injured.
Midfielder Bryson, 33, will have surgery, having struggled with an ankle problem since joining in the summer.
Full-back Leigh, 25, has played in central midfield as injury cover and has a stress fracture of his shin.
And the Dons could be without Sam Cosgrove for two games if their appeal against his red card against Celtic proves unsuccessful.
The club's top scorer with 20 goals was dismissed for a challenge on Kristoffer Ajer as Aberdeen lost 2-1 in Glasgow on Saturday, but manager Derek McInnes said an appeal against referee Euan Anderson's decision would be lodged.
And McInnes said on Monday: "I am hopeful, the reason we have appealed it is because we believe we have a chance to right a wrong. I am hoping common sense prevails and we get the right decision."
The Dons host Livingston on Boxing Day before travelling to face Hearts on Sunday.
"Obviously I have got a team in mind," added McInnes. "We will train tomorrow, we will see where we are, we will train Christmas day and pick the best team available and hopefully Sam is part of that.
"We had the punishment already on Saturday with Sam getting sent off the pitch at such a critical part of the game, because we were still in the game. For Sam to be punished again would be extremely harsh on us.
"The squad is quite tight at the minute, when you lose a few players at any given time it does put a strain on the squad.
"Hopefully we can try and be good enough with our work to try and get maybe one or two in. That would help not only supplement the squad on the injury situation but also improve the team."