He made 70 appearances for United since joining them from Wigan four years ago in a £2.5million move, which City received nothing from after the Latics bought out the sell-on clause.
He's been in and out of the side this season, making a couple of high profile mistakes, but was picked by Sir Alex Ferguson for the Red Devils' FA Cup Final defeat, which proved to be his last appearance for the club.
The Northern Irish international was a Hull City trainee, and he went on to make 50 appearances for the first team before being sold to Wigan in 1997 for £350,000. He still has ties with Hull as it was the city where he met his wife, although a return is unlikely as he is reported to be after wages of £20,000 a week.