Manchester City striker Harry Bunn has suffered a knee injury on-loan at Crewe.
Bunn collapsed in agony clutching his knee on the hour against Tranmere Rovers.
Alex boss Steve Davis said: "Harry twisted funny on his knee but we won't know how bad it is until we have looked at it properly.
"If it is an injury that is going to keep him out for several months, then he will go back to Man City and I will have to look into the loan market to bring someone else in."