The 19-year-old had been among the goals for Glyn Hodges' reserve side before the injury, and had made it onto the senior side's bench for the first time for September's derby at Old Trafford.
Ball told City's website: "Hopefully it's going to be three to four weeks before I am back in training, and hopefully playing. I'm looking forward to it, because usually if I have just one day without kicking a ball I'm raring to go. I know I've only been out two weeks, but it's killing me! I'm just looking forward to being able to kick a ball again."