The City striker sustained a thigh injury in the weekend clash against Coventry City and manager Gary Johnson is unsure as to how long he will be without the service's of his leading goalscorer, who sat out Tuesday night's defeat at Watford.
"He could be out for some time," Johnson has said.
"He has a large haematoma in his thigh and it usually takes a couple of weeks for something like that to clear up.
"It's going to be a matter of how many games he misses."