Cape Town - Younes Kaboul is closing in on a move to Watford after Sunderland accepted a transfer bid from Walter Mazzarri's side.
The 30-year-old former Auxerre and Portsmouth centre-back joined the Black Cats from Tottenhan in 2015, and despite performing well for the club last season, has made the request to leave.
He will discuss personal terms with the Hornets before any deal can be concluded.
Kaboul thanked the club's fans for all of their support on the Sunderland official website.
He said: "This is not an easy situation for me, but the club and the manager have shown an understanding of my personal circumstances and I am grateful for that.
"The Sunderland fans have supported me fantastically well since I came to the club, they gave me my passion back and I sincerely thank them for that.
"I hope they understand that I have made this incredibly difficult decision for me."