Rangers manager Walter Smith admits he is bracing himself for the news that Lee McCulloch is out for the rest of the season.
The midfielder, 32, will visit a specialist on Tuesday to determine whether he will require surgery on the knee problem which kept him out of Sunday's Old Firm derby. McCulloch had been playing through the pain barrier with a cyst in his knee since pre-season but was forced out of last Wednesday's Clydesdale Bank Premier League game against Hearts.
Smith told www.rangers.co.uk: "It could well be the case that Lee is out for the rest of the season and we're preparing for that aspect. If an operation is necessary, he'll be out until the end of the campaign but we'll see what the situation is once he has been assessed."
Rangers were twice pegged back by Celtic in the Scottish Cup clash at Ibrox and Smith says the absence of McCulloch had a big part to play as the fifth-round tie ended 2-2.
He added: "I don't think there's any doubt we missed Lee yesterday and the bit of stability he provides.
"If you were looking at him over the period, I think he was heading towards being our Player of the Year this year. His performances have been fantastic.
"Maurice Edu and Jamie Ness are different types of players but that's something we'll have to try to cover for in the latter stages of the season if we are to be without Lee."