Ipswich striker Nicky Forster is to undergo a cartilage operation and will be out for up to six weeks. Town boss Joe Royle said: "He felt it last week. We're not sure exactly when it happened but he is not right and we must clear it up as soon as possible.
"It is frustrating because he has looked very sharp. Let's hope we are getting all our bad luck with injuries over at the start of the season."
Ipswich defender Jason De Vos is also still sidelined with broken ribs.
Club physio Dave Williams added: "It is not an injury that you can treat.
"He can only go by the doctor's advice and take things at the pace he's told - and let nature take its course."