Dons veteran Andy Considine will not feature for Aberdeen until after Christmas after suffering a cruciate ligament injury last week against Qarabağ FK in Baku.
Stephen Glass believes the poor surface in the stadium in Baku contributed to the damage.
The Dons defender was stretchered off during last week’s 1-0 loss to Qarabağ FK.
The manager said: “Andy went to see a specialist yesterday, he has today had his cruciate repaired so he is going to be out beyond Christmas,” the Aberdeen manager said. “It is something that he will be able to get back from, he is a great professional, and we believe he will come back strong and ready to go not too long after Christmas hopefully.
“The first concern is for Andy himself. He is in good spirits but he is obviously going to be disappointed because he has been brilliant since we came in.
“He is an unbelievable example to young players at the club, he is a great professional, one of the best that I have ever encountered.
“So we are hugely disappointed for him but we are here to support him in his rehab and as soon as he is back in the building, everyone is here to help him get back on track.”
The Dons host Qarabağ FK in the second leg of our Europa Conference League play-off on Thursday.