Rangers midfielder Lee McCulloch is struggling to play again this season after undergoing surgery on a long-standing knee injury.
McCulloch has been playing through the pain barrier in recent months and finally underwent an operation on Tuesday.
He has sat out Rangers' last two matches against Celtic and Motherwell after being forced off just 20 minutes into the 1-0 win over Hearts earlier this month.
The Scotland international will now start his rehabilitation and Gers boss Walter Smith expects the 32-year-old to miss much of the remainder of the season.
Smith said: "A lot depends on the player's reaction to the operation.
"He got the cyst removed and the operation went successfully.
"At the present moment, we would look at him being out for the vast majority of the season."