Coventry fear defender Ben Turner could be facing a spell of up to six weeks on the sidelines with a knee injury.
The talented 22-year-old has been one of the Sky Blues' most impressive players this season with a series of assured displays in Aidy Boothroyd's backline.
Turner was absent from Tuesday night's 2-1 defeat to Nottingham Forest which left Coventry sixth in the Championship table and may now be out of action until the festive period.
With Turner out of action, James McPake and Nathan Cameron are likely to be in contention for further opportunities in the starting XI.
Scottish defender McPake started the City Ground defeat, but was forced off early in the second half with a back problem.
Cameron came on in his place, but the former Livingston and Morton man is hoping to be fit for Saturday's trip to struggling Crystal Palace.
McPake told the Coventry Evening Telegraph: "I have had a stiff back since last Thursday so I always knew it was going to flare up at some point.
"I got to 65 minutes and it just tightened up and my hamstring was tightening up as well so I came off as a precaution because I don't want to be out for six weeks with a tear or something.
"I am hoping it settles down for Saturday.
"It settled down quickly last week when I couldn't even bend my back, never mind play, so if it recovers that quickly this time then I will be fine."