Mark O'Brien has joined Jeff Hendrick and Steve Davies on the casualty list for Derby ahead of the visit of West Ham on Saturday.
O'Brien has undergone knee surgery after damaging his anterior cruciate ligament in training on Tuesday and the defender is set to miss the remainder of the season.
Midfielder Hendrick was ruled out of the Christmas and New Year programme after damaging ankle ligaments during the defeat at Ipswich on December 17.
Davies has been sidelined since suffering a fractured skull against Southampton in mid-October. The striker could soon return depending on the results of his latest scan.
Fit-again Theo Robinson and fellow forward Tamas Priskin, along with midfielder Ben Davies, are options for manager Nigel Clough, who could recall centre-half Jake Buxton to the squad following the injury to O'Brien.
Robinson, Ben Davies and midfielder Craig Bryson go into the final game of 2001 on four yellow cards. They will escape a suspension if they can avoid collecting another because the cut-off point for five bookings is the end of the year.
West Ham have four players suspended for the trip to Pride Park.
Skipper Kevin Nolan, winger Julien Faubert and defender George McCartney all travelled to Birmingham on Boxing Day knowing a yellow card would earn them a one-match ban and all three duly got themselves booked.
Midfielder Jack Collison is still suspended following his red card against Reading a fortnight ago.
The Hammers also have a big injury list with Abdoulaye Faye (thigh), Winston Reid (shoulder), Guy Demel (thigh), Matt Taylor (calf), David Bentley (knee) and Sam Baldock (hamstring) all receiving treatment.
Boss Sam Allardyce hopes Faye will be available, otherwise James Tomkins is his only fit centre-half, while striker Baldock is also pushing to return after a month on the sidelines.
O'Brien has undergone knee surgery after damaging his anterior cruciate ligament in training on Tuesday and the defender is set to miss the remainder of the season.
Midfielder Hendrick was ruled out of the Christmas and New Year programme after damaging ankle ligaments during the defeat at Ipswich on December 17.
Davies has been sidelined since suffering a fractured skull against Southampton in mid-October. The striker could soon return depending on the results of his latest scan.
Fit-again Theo Robinson and fellow forward Tamas Priskin, along with midfielder Ben Davies, are options for manager Nigel Clough, who could recall centre-half Jake Buxton to the squad following the injury to O'Brien.
Robinson, Ben Davies and midfielder Craig Bryson go into the final game of 2001 on four yellow cards. They will escape a suspension if they can avoid collecting another because the cut-off point for five bookings is the end of the year.
West Ham have four players suspended for the trip to Pride Park.
Skipper Kevin Nolan, winger Julien Faubert and defender George McCartney all travelled to Birmingham on Boxing Day knowing a yellow card would earn them a one-match ban and all three duly got themselves booked.
Midfielder Jack Collison is still suspended following his red card against Reading a fortnight ago.
The Hammers also have a big injury list with Abdoulaye Faye (thigh), Winston Reid (shoulder), Guy Demel (thigh), Matt Taylor (calf), David Bentley (knee) and Sam Baldock (hamstring) all receiving treatment.
Boss Sam Allardyce hopes Faye will be available, otherwise James Tomkins is his only fit centre-half, while striker Baldock is also pushing to return after a month on the sidelines.