We profile three men who've played for both clubs.
Don Goodman signed for the Black Cats from West Brom back in 1991 – Denis Smith paid a then club record of £900,000 for the Bradford-born forward whom he saw as the man to replace outgoing striker Marco Gabbiadini.
Goodman settled straight into life at Roker Park, netting a hat-trick in only his seventh appearance and going on to lead the club’s scoring charts with 11 goals in 22 games.
He went on to make 116 appearances for Sunderland, scoring 40 goals before a £1.1m move to Wolverhampton Wanderers.
Stanislav Varga signed for the Black Cats in the summer of 2000 and picked up the man of the match award on his debut when Niall Quinn’s goal earned Sunderland a 1-0 victory over Sunderland.
A long-term injury put Varga down the centre-defence pecking order and first-team opportunities were limited.
As a result, Varga joined West Brom on loan and went on to make four appearances for the Baggies towards the end of the 2001-02 season.
Varga was re-signed for Sunderland in 2006 by Roy Keane and went on to make a further 20 appearances for the Black Cats.
Haas joined Sunderland in 2001 and made 27 appearances for the Black Cats before going on loan to FC Basel in 2002.
By the time of Haas’ return in 2003, the Swiss international had fallen out of favour at the Stadium of Light and signed for West Brom, making 46 appearances for the Baggies.