Newcastle United are in discussions with Ciaran Clark having activated the Aston Villa defender's release clause of £5m.
The 26-year-old Republic of Ireland international Clark has an escape clause in his current deal with Villa, and despite having four years left to run on his contract he may now leave.
Clark can play at centre-back, left-back or in a holding midfield role.
He is currently preparing for the Sky Bet Championship season after suffering relegation with Villa in May. Clark also played twice for Ireland at Euro 2016 in France.
Villa boss Roberto Di Matteo is likely to be disappointed if Clark left Villa Park with the new boss saying recently: "Ciaran is a Villa man, a Villa boy, he has pledged his future to us. He will be staying with us.
"He is very happy to be with us, to stay here. I know he has a long-term contract as well."
The Magpies are also attempting to sign Hull City's Mo Diame.
Sky sources understand United have triggered the £4.5m release clause of the midfielder with a fee having been agreed between the two clubs.
The 29-year-old, who joined Hull from West Ham in 2014, has made 50 appearances for the Tigers and scored 13 goals.
Newcastle open their Championship campaign on Friday at Fulham, live onSky Sports 1 HD from 7pm.