George McCartney joined West Ham from Sunderland in 2006

West Ham defender George McCartney has rejoined Sunderland.

Linked with a return to the Black Cats in July, Sunderland have signed the the Northern Ireland international defender for an undisclosed fee.

West Ham turned down a �4.5m offer in early July but Sunderland made a renewed bid of around �6m for the 27-year-old Northern Ireland player.

McCartney underwent a medical at Sunderland on Monday, before agreeing a five-year contract with the Black Cats.

McCartney came through the academy at Sunderland and made his debut in a 3-0 League Cup win against Luton in September 2000.

He made 157 appearances for the Black Cats before moving to West Ham in a �1m deal in August 2006.

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"George's experience will prove invaluable and he shouldn't take long to settle in as he knows a lot of the lads already and obviously he knows the club inside out," said Sunderland boss Roy Keane.

"I'm happy with my squad now. We have strength in depth and healthy competition for places in all areas."

McCartney added: "The club has moved on over the last two years and I think there are exciting times ahead."