The 25-year-old has signed a new three-year contract that will keep him with the Black Cats until the summer of 2013.
Richardson joined Sunderland from United almost three years ago and have made 85 appearances for the Black Cats.
The 25-year-old has signed a new three-year contract that will keep him with the Black Cats until the summer of 2013.
Richardson joined Sunderland from United almost three years ago and have made 85 appearances for the Black Cats.
