The former Newcastle and Sunderland forward is awaiting the results of a scan after lasting just 30 minutes of the 4-0 win over Doncaster on Saturday.
He may be joined on the sidelines by defensive pair Kevin McNaughton and Darcy Blake, with the former limping off against Rovers in the 18th minute with a hamstring strain.
Blake, meanwhile, injured his ankle during the warm-up and both players are unlikely to feature at London Road.
Midfielder Jason Koumas will be pushing for a starting berth and though midfield duo Stephen McPhail and Aaron Wildig have returned to training following their respective knee injuries, neither player is expected to play.
