Derby County top scorer Steven Davies is set to be on the sidelines for 12 weeks after fracturing his skull in Saturday's 1-1 draw with Southampton.
The striker, who has five goals in 11 games this season, was hurt just above the eyebrow and it was thought he would be out for around six weeks.
But manager Nigel Clough told BBC Radio Derby: "It was a bit worse when they went in and operated.
"It's right on his forehead and you can't protect it with a mask."
Clough added: "He's our leading goalscorer and we well certainly miss him.
"He has had such bad luck with injuries. The end of last season and this season was probably the longest run in his career.
"He has to get his head down and get as fit as he can to come back in January."