On-loan Watford defender Tommie Hoban was today set to undergo shoulder surgery that is expected to rule him out until January.
The 24-year-old suffered the injury when falling awkwardly in scoring in the 1-1 draw at Hibs on August 28.
His operation had been delayed as the former Republic of Ireland Under-21 international’s partner was waiting to give birth.
The baby arrived last Thursday and now Hoban will go under the knife in England and undergo his early rehabilitation with parent club Watford.
Aberdeen boss Derek McInnes said: “Tommie is getting his operation.
“We were waiting until his partner had a baby and she gave birth on Thursday.
“He has now travelled down to get that operation. Tommie will do the initial part of his rehab down there and stay with the medical department at Watford.”
Hoban’s switch from the Premier League Wasps has been hindered by injury since arriving on a season-long loan.
He started both Europa League ties against Burnley but suffered a knee injury in the 3-1 extra-time away defeat to the Clarets that ruled him out of the first three domestic games of the season.
He returned to action at Easter Road only to suffer another injury setback.
McInnes said: “Hopefully the surgeon finds the operation as we expect and we can have Tommie back with us in January.”
Hoban was just one of six Aberdeen players ruled out by injury for the 1-0 defeat of Motherwell.
There is some respite as attacker Frank Ross is set to return having missed the last two games with a back injury. However, Lewis Ferguson (knee), Scott Wright (ankle), Mark Reynolds (knee) and Greg Tansey (groin) are out.
McInnes said: “Frank Ross trained on Sunday and will be added to the squad.”
On-loan Manchester United striker James Wilson returned from a hamstring injury to make his first Dons start in the defeat of Well.
The 22-year-old grabbed the vital goal and is set to lead the line in the Betfred Cup quarter-final at Hibs’ Easter Road tonight.
“We have to be fair to James as he has not played a lot of competitive football in recent times,” added McInnes.
“No amount of training will get him there. It will be a combination of match time and his training.
“Whether we can get James 45 minutes or 60 minutes the intention is to get him built up to fitness so that he can give us a 90-minute performance.”