CRAIG Bryson is a major injury doubt for Derby County's FA Cup clash against Chelsea tomorrow.
Bryson was replaced at half-time during the defeat by Wigan Athletic on New Year's Day due to a groin problem brought on by a knock he suffered against Huddersfield on Boxing Day.
Derby will assess the Scottish international's fitness today.
"He could be struggling and the key is not to take any risks with him," said head coach Steve McClaren. "I hope he can play, because he has been one of our key players."
Bryson has missed only one of Derby's fixtures this season and the midfielder has scored 11 goals.
"Being without Bryson would be a blow for us but we have Jeff Hendrick chomping at bit," McClaren added.
Hendrick came on for Bryson against Wigan.
Derby will be without striker Johnny Russell for the visit of Chelsea.
He has undergone surgery to repair a fractured cheekbone, although he could return to action by the end of the month.
Russell suffered the injury against Wigan Athletic. He has already been sidelined with a broken leg earlier in the season, the same leg he broke playing for Dundee United last season.
"It is another blow for him," McClaren said.
"I saw the incident again, it was a bad challenge and Johnny carried on playing, remarkably.
"He has now had three fractures in the last 10 months or so. He is having some bad luck."
Russell, who signed in the summer, has scored five goals in 14 starts this season.
