The 24-year-old becomes Paolo Di Canio's 11th summer signing after seeing Jonjo Shelvey and Jonathan De Guzman move ahead of him in the pecking order at the Liberty Stadium
The 24-year-old becomes manager Paolo Di Canio’s 11th summer signing after agreeing to leave the Liberty Stadium in search of first-team football, although he is ineligible for Saturday’s game against Crystal Palace.
"Sunderland have signed midfielder Ki Sung-Yueng from Swansea City on a season-long loan," a statement on the club’s official website read.
"The 24-year-old South Korean international is the club's 11th summer signing. He is not eligible for today's game against Crystal Palace."
Ki was a regular starter for Swansea last season, making 38 appearances in all competitions.
However, the Swans have since strengthened their midfield with the capture of Liverpool midfielder Jonjo Shelvey and the re-signing of Jonathan De Guzman on loan.
Ki has thus opted for a move to the Stadium of Light, where he will link-up with fellow midfield arrivals Emanuele Giaccherini, Cabral and El Hadji Ba.