Hearts midfielder Ruben Palazuelos is facing up to six weeks on the sidelines through injury.
Palazuelos sustained a knee injury in the recent defeat by Aberdeen and he has seen a specialist to find out the full extent of the problem.
The 26-year-old has been told to rest the injury and Hearts boss Jim Jefferies does not expect him back for at least six weeks
"Ruben has been to see a specialist and isn't to do anything for three weeks," said Jefferies.
"Hopefully the rest he gets will help but he certainly will be missing for at least five or six weeks."
Meanwhile, Andrew Driver is set to miss Wednesday's league clash with Celtic after suffering a reaction to his knee problem in the Co-operative Insurance Cup semi-final defeat by St Mirren last Tuesday.
Jefferies is hopeful the problem is not too serious and is confident the winger will be back in action in the near future.
"Andrew has had a wee reaction," added Jefferies.
"The pitch wasn't the best for someone coming back from an injury like that.
"But he's improving as the days go on. It looked like he could be out for a couple of weeks but he says he's feeling better."