Hearts midfielder Suso Santana has been ruled out until mid-December after having surgery on a hernia problem.
Defender Marius Zaliukas has gone to his native Lithuania to be treated for his ankle injury, and is expected to return to fitness around the same time.
But captain Michael Stewart and striker Christian Nade should be passed fit for Saturday's Edinburgh derby.
Suso told the Hearts website: "It's disappointing to miss the derby but I hope the players get a good result."
The 24-year-old Spaniard, who joined in the summer, has played through the pain barrier in recent weeks.
MY SPORT: DEBATEBut his manager Csaba Laszlo said previously that he wanted his player to have the procedure done now to prevent further damage.
"I had the problem for a little while and played a few matches with it and it was decided that an operation was the best thing to do," added Suso.
"The doctors have told me I'm probably looking at six weeks but I want to get back before that.
"Hopefully, I can do it in four weeks as I want to get back into the team as quickly as possible."
Hearts will also be without Eggert Jonsson for the visit of Hibernian after the versatile player was sent off against Motherwell.
Stewart was rested for the 1-0 defeat at Fir Park since he has been suffering from a sore ankle, while Nade was carried off on a stretcher shortly before the hour mark.
Laryea Kingston (hamstring), Callum Elliot (knee) and David Templeton (foot) are all still some way from a first team return.
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