The 25-year-old can speak to clubs now over a pre-contract move in the summer with less than six months remaining on his present deal at Tynecastle.
Rangers are one of the clubs rumoured to be interested but will face competition from the English Championship if that does materialise into an offer.
Stoke City, where Souttar’s brother Harry plays, are another side linked but Sheffield United have revealed they are monitoring the situation of Souttar, who capped a return from serious knee injury with an international goal for Scotland in the 2-0 World Cup qualifying win over Denmark, late last year.
Paul Heckingbottom, former manager of Hearts’ city rivals Hibs and now in charge of the Blades confirmed his knowledge of the defender, and he is on their shortlist for strengthening the Bramall Lane defence.
"He's one of a few that we have been looking at," the United boss confirmed when asked about Souttar. "We highlighted positions we need players in and he's one in that position.
“We would be foolish not to have a look at him, he's a free transfer in the summer.
“I am not going to say if we are going to do it but certainly someone we have looked at.
“I know him from my time in Scotland a good player and I am sure we will be linked with more players, some will be right and some will be way off the mark.”