Martin O'Neill has revealed that Nicklas Bendtner is set for a lengthy spell on the sidelines after his facial injuries were found to be worse than first thought.
Sunderland announced earlier this week that Bendtner had suffered a broken nose when he was caught in the face by Angel Rangel's boot during Saturday's game against Swansea.
However, O'Neill has now admitted that the damage is more extensive and as a result, Bendtner is likely to miss several games, starting with Sunday's FA Cup fourth-round clash with neighbours Middlesbrough.
He told the Sunderland Echo: "He's got a bit more than a broken nose.
"It's difficult to put a timescale on it, but it's going to be lengthy.
"We thought at one stage he might be okay. The early signs, even on Sunday morning, were that it looked as if it might be okay.
"But he's going to be out for a number of weeks now, which is definitely a blow to us. He has a few cracks and we just have to bide our time with that.
"That's a big blow to us and to the lad himself, who was beginning to enjoy a decent spell of football for us."
Teenager Connor Wickham took Bendtner's place against the Swans, while Ji Dong-won was among the substitutes and Fraizer Campbell is close to a return after his latest knee injury.