London: Sunderland signed Netherlands defender Patrick van Aanholt from Chelsea for an undisclosed fee on Friday.
Van Aanholt agreed a four-year contract with the Premier League club after failing to break into the first-team at Stamford Bridge.
The 23-year-old is Sunderland`s fourth signing of the pre-season, following on from the arrivals of defender Billy Jones, goalkeeper Costel Pantilimon and midfielder Jordi Gomez.
Sunderland manager Gus Poyet was keen to sign a left-back after Marcos Alonso`s loan spell from Fiorentina finished at the end of last term.
Van Aanholt made just eight appearances for Chelsea in his five-year spell with the west London club and was sent out on loan to Coventry in 2009, Newcastle in 2010 and Leicester and then Wigan in 2011.
He spent the last two-and-a-half seasons on loan at Dutch outfit Vitesse Arnhem and has been capped twice at senior international level.
Van Aanholt was named in Louis van Gaal`s 30-man provisional Holland squad ahead of the recent World Cup, but did not make the final 23-man group for the tournament in Brazil.