Coventry midfielder Don Hutchison looks set to be sidelined for up to three months with a broken ankle.
The 35-year-old was stretchered off against Sheffield Wednesday last Saturday following a collision with Marcus Tudgay.
It was initially suspected that he had damaged ligaments, but x-rays have shown the injury to be worse than anticipated.
A club spokesperson said: "As well as breaking his ankle, Don Hutchison has also sustained ruptured ligaments and severe bone bruising, which will see him sidelined until well into the New Year."
On-loan duo Richard Duffy and Clive Clarke, meanwhile, have extended their stays at The Ricoh Arena until January 1.
Their initial month-long deals expired following the 3-1 defeat to Wednesday, but Sky Blues boss Micky Adams has reached agreements with the players' clubs.
Portsmouth's Duffy is enjoying his third spell with Coventry, while Clarke has played five times since joining from Sunderland last month.
Both players are eligible for the New Year's day clash against Leeds at Elland Road.