City are due to make a further payment to Leeds for Fowler when he makes his 60th appearance but the striker has been left out of the side whilst on 59 games and won't figure again until next month at the earliest.
Fowler hasn't played since September 11 and his continued absence is denying Leeds valuable cash.
United, who contribute in excess of £500k-a-year towards Fowler's wages, are thought to be owed around £1.5m in further payments for the player.
Fowler joined City in January 2003 in a deal worth up to £6m.