The 31-year-old former Aberdeen star is keen to get regular football elsewhere.
Sunderland boss Steve Bruce told the club’s official website: “This decision has been taken with Russell to give him an opportunity to find a club where he can fulfil his desire to play more first team football.
“He has been very unfortunate with injuries since he came here but his attitude and determination to get back playing have been exemplary.
“We wish him all the very best for the future.”
