Aberdeen have been rocked by the news that defender Andrew Considine is out until after Christmas after having surgery on his cruciate.
The 34-year-old Scotland international suffered a knee injury in the first leg of the Europa League conference play-off against Qarabag in Baku last week and had an operation on Wednesday morning.
Ahead of the return game at Pittodrie on Thursday, where the Dons trail 1-0, manager Stephen Glass said: "Andy went to see a specialist yesterday, he has today had his cruciate repaired so he is going to be out beyond Christmas.
"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."
As well as the chance to play European group-stage football, qualifying through to the group stages will also bring financial rewards to the Pittodrie club and sums of £2.5million upwards have been reported.
Glass, whose side beat BK Hacken and Breidablik in previous qualifiers, insists all the attention is on getting past Qarabag.
He said: "That's what professionals do, you plan and prepare for the here and now.
"We can control what happens in the game tomorrow night, that is the sole focus.
"Anything that happens off the back of a win or getting through is what happens but professionals prepare for the 90 minutes, you try to win a game.
"We are excited and looking forward to it. I think it is going to be a special occasion.
"When we started preparing for the Hacken game, we didn't talk about this game but we were hopeful that we were going into this situation.
"We were hopeful going away to Azerbaijan that we would still be in a position to win the game which we are.
"We know what is at stake for the club, we know what the future holds if we get through and it is something the club has been desperate for, for a number of years and we will do everything we can to get there."
Glass also confirmed that Ryan Hedges would be out until after the upcoming international break with a hamstring problem.
Jonny Hayes and Connor McLennan will be given every opportunity to prove their fitness after sustaining knocks against Hearts at Tynecastle on Sunday, while Jack MacKenzie is available again after recovering from injury.
