The 22-year-old has undergone a scan to discover the extent of a rib injury suffered during Saturday`s 4-1 defeat at Leeds.
It is feared he may be facing at least three weeks on the sidelines and could, at worst, miss the remainder of the season.
"Paul has undergone a series of scans in hospital and we are expecting the results on Wednesday," manager Billy Davies told the Nottingham Post.
"But he has not recovered as we would have hoped since the weekend. We need to find out what the nature of the problem is."
Source: PA
Source: PA