Aberdeen will be without midfielder Dylan McGeouch for eight weeks after he tore his groin.
The midfielder suffered the injury in Sunday's 3-3 Scottish Premiership draw with Celtic and is expected to be sidelined for the rest of the year.
Manager Derek McInnes says McGeouch's diagnosis is the "worst" possible.
"He tore it just as he came off the side of the pitch, there is a little lip there and he lost his footing on that and overstretched," he said.
However, McInnes said that forwards Ryan Edmondson and Marley Watkins should be fit for Sunday's Scottish Cup semi-final with Celtic.