Aberdeen boss Craig Brown has revealed Rob Milsom has been ruled out for the rest of the season through injury.
Milsom missed Saturday's draw at Rangers after being forced to undergo knee surgery on Friday.
The 25-year-old will now be sidelined for the remainder of the campaign and Brown admitted it was a major blow for the Dons.
"He is likely to be out for the season," admitted Brown.
"He had a knee operation in London and the leg was examined and there was more damage than first feared.
"The surgeon said he will not play this season so that's a major blow for us."