'Michael has a hamstring injury and medical staff say he could be out for a month,' said chairman Peter Ridsdale.
That means he's likely to miss the home games with Sunderland, Sheff Utd and Stoke and the trip to Burnley on Easter Monday.
Chopra is the Championships leading scorer and his loss will be a huge blow.
City have signed Warren Feeney today in the hope he can contribute to the goals for column as the Bluebirds aim for a place in the play offs.