Bristol City have secured the services of former Middlesbrough defender Matthew Bates on a two-month deal.
The 25-year-old free agent will help to strengthen to the club's defence, penning a deal until 16 January on the back of a successful spell training at Ashton Gate.
Manager Derek McInnes said: "He's proved his fitness and is a quality addition to our squad.
"He's had a poor time with injuries but has demonstrated the strength to come back on each occasion.
"We were more than happy to take a look at somebody with his quality and he has shown his fitness, including playing in a practice match in the week.
"He offers us a good option and is a good person too. It's a low-risk deal until mid-January, which gives him the opportunity to stake a claim for an extended stay if all goes well."
It is a big boost for the centre-half, FA Youth Cup winner with Boro in 2004, who featured for his hometown club over 100 times in a six-year period.