The 31-year-old defender has been a regular for the Magpies since joining in 2010 but is believed to be on his way out of St James', as new boss Steve McClaren looks to reinvigorate an ailing squad with fresh talent.
Leeds have now been linked with the former Watford and Portsmouth man but with his contract not expiring until next summer, Newcastle would more than likely demand a fee.
But with Anderlecht defender Chancel Mbemba set to re-join former teammate Aleksandar Mitrovic at the club later this month, Williamson is expected to leave St James’ Park before the transfer window closes.