Sunderland have reportedly had a £4m bid for Ashley Williams rejected by Swansea City.
The Black Cats are understood to have tabled their offer for the 29-year-old defender at the start of the month.
However, the Wearside club have had their bid dismissed by their Premier League rivals, according to Sky Sports News.
Sunderland, Arsenal and Queens Park Rangers have all been linked with Williams in recent weeks.
The centre-back, who is out of contract next summer, recently opened talks with the Swans over a new deal.