A look at players who have played for both teams.
Thomas Butler (Sunderland 1998 – 2004, Swansea City 2006 – 2012)
Thomas Butler started his career at Sunderland, and as a youngster forged himself a reputation as one of the Republic of Ireland's brightest stars. He made his Black Cats debut in a League Cup victory over Walsal in 1999. The following season the winger was loaned to Darlington and in the seasons that followed her failed to make an impact at the Stadium of Light making just 17 starts and 12 substitute appearances. In 2004 Butler left Sunderland due to personal reasons but later started playing football again following a trial with Dunfermline. After spending a season with Hartlepool United, Butler signed for Swansea City in the summer of 2006. The Irishman spent five seasons in South Wales, amassing 126 appearances and nine goals, before being released in January 2012 without making a Barclays Premier League appearance for the Swans.
Trevor Ford (Swansea 1942 – 1947, Sunderland 1950 – 1954)
Sunderland’s £30,000 striker – a British football transfer record when he signed for 'Bank of England' club from Aston Villa – started his career at Swansea. The original celebrity footballer made 16 appearances for the Swans, nabbing nine goals. After a year with his hometown club 27 year-old Ford moved to Aston Villa, scoring 61 goals in 128 appearances. He arrived at Sunderland for a record-breaking fee and a scoring record just as prolific. Over the course of his four years on Wearside Ford found the back of the net on 67 times occasions duting 108 outings.
Andy Melville (Swansea City 1986 – 1990, Sunderland 1993 – 1999)
Sunderland’s most capped Welsh international defender made his senior playing debut in both the league and FA Cup for Swansea City before he was 17 year-old. After 185 appearances for the Swans he moved to Oxford United for a fee of £275,000 just two weeks before his 21st birthday. Three seasons later the defender arrived at Roker Park and his name was the first on the team sheet under three different managers during his first two seasons. However, the arrival of Jody Craddock in 1997 saw chances limited for Melville and after a number of loan spells he left the club on a Bosman free transfer to go and work with former team mate Paul Bracewell who had just taken over at Fulham.