The Blues full back has already unsuccessfully attempted one comeback from a troublesome knee injury with two Reserve team appearances this season.
Grainger lasted 66 minutes in his first Reserves outing of the season in the away fixture with Man Utd on October 2nd followed by a full 90 minutes for Keith Bertschins side in the 2-1 home win against Bolton six days later.
Now, after undergoing a series of injections to the knee, Grainger is expected to begin his latest comeback in the Reserves game against Man Utd at St. Andrews on Wednesday 14th January.
A key member of Blues promotion winning side of 2001-2, Graingers last appearance for Steve Bruce's first team was almost twelve months ago in the home defeat to Arsenal last season.