The 22-year-old suffered a knee injury at Kidderminster a month ago, and it was thought he would be returning to training at this point.
However, it has emerged that he is unlikely to play again this season.
Manager Peter Taylor said: "Mike suffered the injury before I came to the club and we all hoped it would not be a major problem.
"However, I think we've suspected something was wrong. Once the swelling around the knee went down, the specialist discovered the ligament damage.
"It's a blow for Mike and for us because I know what a talented young player he is. It is going to be a long lay-off and I wouldn't think he will play again this season although you never know. Our best wishes go to him and let's hope he's back in action as quickly as possible."
City do have cover in place after signing Carl Regan until the end of next season on a free transfer. Matt Bloomer is also available after returning from his loan spell at Telford, and he will hope to push for a first team place with Edwards out of the picture.
Meanwhile, Michael Branch will be with the Tigers for another month after extending his loan deal from Wolves.