Sunderland defender Wes Brown has suffered a setback in his bid to recover from a knee injury that will now see him out until the New Year.
Brown, 33, joined from Manchester United last summer but has endured a stop-start time to his career on Wearside due to injuries, including his current problem which he suffered during the club's pre-season tour of Korea.
"Wes had a setback in his recovery. He was training with us and doing well when he had a setback and we will assess how much of a setback it is," Sunderland manager Martin O'Neill said.
"He wants to see a specialist who was on holiday last week so he hadn't ability to do that. The fella is down in London, he knows Wes inside out and he is the man Wes wants to see. Wes himself is really frustrated with it all.
"Having come to a new club he was wanting to make an impression. It's a tough time for him in his career and really frustrating. He wanted to make a mark but unfortunately the comeback has not been easy to overcome."
The news is a further blow to O'Neill's defensive options, with the Sunderland boss already having to cope without Titus Bramble due to a hip problem.
That leaves the club with only Matt Killgallon as cover for the first choice pairing of Carlos Cuellar and John O'Shea - the former Leeds United defender being named as a substitute in Tuesday's 1-0 Capital One Cup defeat to Middlesbrough.