The mdifielder signed by Peter Reid from Portsmouth, broke his leg six months before joining City but has suffered from complications ever since.
Sherwood has played ten times plus one substitute appearance this season and has spent most of the the time doing television work which included the Norwich v Manchester City game on Monday night.
Micky Adams told the club website: "The scans have shown a problem and he'll be going for a further scan in a week or so. "We don't expect Tim to play again this season but it is in no way a career-threatening injury. "We're hopeful he will be back in action next season so we'll start again from there."