James Meredith is suffering from glandular fever, Phil Parkinson revealed this afternoon.
And the City boss fears the left back, one of the best performers of the campaign, could possibly miss the rest of the season.
Meredith spent the weekend in hospital and Parkinson admitted: "We don't know how severe a strain it is, whether he is out for the season or just a few weeks.
"We're waiting to hear from the doctor but he's been in hospital because he is very ill."
Ryan Dickson arrived last week on loan from Southampton as cover.