Sunderland have confirmed that Patrick van Aanholt has been given permission to hold talks with Crystal Palace after the two parties agreed a fee.
Palace manager Sam Allardyce is keen to reunite with the defender, who played under the 62-year-old at Sunderland last season.
The Black Cats rejected a £7m bid earlier this month, but now, according to Sky Sports News, an offer in the region of £14m has been accepted by the Eagles.
In a statement on their official website, Sunderland confirmed that Van Aanholt, who joined the North-East outfit from Chelsea in 2014, submitted a transfer request.
Chief executive Martin Bain said: "If a player openly states he does not want to play for our club, then it is clear that we have a decision to make. In this instance and in regard to this particular player, we have done what we feel is right for Sunderland, which will always be our priority."
Both clubs are battling relegation, with Sunderland at the bottom of the Premier League table, three points from safety, while Palace are two adrift.