St Johnstone's Ryan McGowan will be on the sidelines for months.
The versatile defender, who has also played in the middle of the park this term, has a serious groin problem.
Disappointed manager Callum Davidson said the scan results revealed that the news was not good.
“He’s got a badly torn groin,” explained Davidson, who takes his players to Motherwell for a crunch league game on Wednesday night.
“He will be out for the foreseeable future and a little bit more, so it’s a real blow for him and for us.
“He’s done a fair bit of damage to it. He didn’t have any pain, which was a worry because there was loads of bruising there but he didn’t feel anything.
“It’s a real shame because Ryan has been very good and he’s versatile, he can play a number of positions for us.
“So with the last couple of days of the window we are assessing what we need.
“We are working on things but it’s frustrating at this time of year because things are constantly moving.
“We thought we had someone at the end of last week but it didn’t happen, but we’re still working on it.
“Hopefully over the next 48 hours we will have some fresh faces in and some players will be heading elsewhere.”