The 27-year-old former Scunthorpe man missed last weekend's defeat to Wolves with a knock to his knee but he will now be kept away from his team-mates for at least the next week.
Manager Derek McInnes was already without a number of first team players including the likes of Lewin Nyatanga and Jon Stead while four of his players are on the comeback trail but are not ready for Championship action just yet.
Stephen McManus, Greg Cunningham, Cole Skuse and Jody Morris have returned to training but the trip to Hillsborough comes too soon for them.
Steven Davies gave his manager a reminder of what he can do with a goal for the reserves in a 1-1 draw with Exeter in midweek, a Robins side that also included winger Paul Anderson who has only played six times for the first team this season.
- Sports & Recreation
- Lewin Nyatanga
- Jon Stead