Kilmarnock manager Kenny Shiels has revealed that Ryan O'Leary could miss the rest of the season and that he has started the hunt for a replacement.
Shiels is allowing the versatile Tim Clancy to join Motherwell to make room for a new central defender.
After suffering a cruciate ligament injury during Sunday's 0-0 draw with Hearts, O'Leary will undergo an operation next month.
"That's six months as a timescale," Shiels told BBC Scotland.
In addition to O'Leary and fellow long-term injury victim David Silva, striker Paul Heffernan is out of this weekend's match against Inverness Caledonian Thistle because of a calf strain.
And, with Clancy poised to complete a free transfer to Motherwell, Shiels is expected to make a decision in the next few days about who he will sign to replace O'Leary.
The Northern Irishman is currently looking at three options.
"It's in the mix, " said Shiels.
"We've got someone training with us tomorrow and we have one from England who would be keen to come, so we're looking at those two angles and we've another coming from Spain, so we'll make our choices around that."
It was Shiels who brought O'Leary back to the club months after he had been released under the previous regime.
And the manager had sympathy for the player who was stretchered off after a goal-line collision during the draw at Rugby Park.
"I feel for Ryan. He's worked so hard, his career's back on track," said Shiels.
"Hopefully he has the strength of character to deal with this injury.
"It's going to be very, very difficult for him and that's when you need good, strong coping strategies and we'll work as best we can on that.
"But Ryan's been very positive about it.
"He's in again today and he's starting his strengthening programme as part of his rehabilitation and he then has an operation around about the middle to late September."