City are sweating over the fitness of Lewin Nyatanga as they prepare to host Boro.
Defender Nyatanga picked up a knee injury in the 2-2 draw with Watford on Tuesday and is rated doubtful for the clash with the Teessiders.
Otherwise, manager Derek McInnes has no new injury or suspension worries as he looks to extend his team's unbeaten run in the Championship to seven matches.
Striker Jon Stead is back in contention for a place in the Robins' matchday squad after shrugging off a groin problem, while defensive duo Louis Carey and Jamie McAllister are both ready for a comeback following their returns from respective knee and ankle injuries.
Fringe players Ryan Taylor (broken metatarsal) and Nicky Hunt (knee) remain sidelined.
Midfielder Barry Robson is a doubt for Boro's trip to the west country.
The Scotland international missed Tuesday night's 2-0 home defeat by promotion-chasing West Ham with a thigh problem and his recovery will be assessed in the run-up to the game.
But while manager Tony Mowbray will hope to have Robson at his disposal, the former Celtic man's chances of being joined in the squad by compatriot Kevin Thomson look remote.
Thomson has missed the last seven games with a hamstring injury and is rated as doubtful for the game at Ashton Gate.
Boro remain in fourth place in the table despite Tuesday night's reverse, but are now eight points adrift of the Hammers in the second and final automatic promotion place.
