Mile Jedinak has been advised to rest as he looks to recover from a shoulder injury.
Jedinak picked up the problem early on in the weekend victory over Ipswich.
Steve Bruce revealed the Aussie ace will be in a sling for the moment and if the issue calms down, he could be ready to play in just over a month.
However, if there are no signs of improvement, he could be set for an operation, which would possibly put him out of action for three months.
He said: “He went to see a specialist in Manchester on Monday.
“He’s been advised to rest and see how it is in the next week to see if it starts to heal itself.
“If it does, we can let nature takes its course and it could be six weeks then.
“If it doesn’t, then there will be an operation which will probably take the best part of 12 weeks.
“We hope the specialist is right and rest is sufficient. Then we could see him back in January.”
Bruce praised the squad for coping with the absence of the team’s big hitters – including John Terry and Jonathan Kodjia.
He admits he will now look to bolster the squad in January as he looks to keep the pressure up at the top of the division.
He added: “To be without Terry, Kodjia, Jedinak is a real blow to us because they are the spine of the team.
“Fair play to the squad for coping very well so far.
“In January, let’s hope we can add to us to help us along the way.”