Hearts are reportedly interested in PEC Zwolle striker Koen Kostons, as they are seeking to add another forward. The 26-year-old Dutch forward joined Zwolle from SC Paderborn last summer. He spent the second part of the season on loan at Kortrijk and has three years remaining on his contract. Hearts would need to pay approximately €1.5 million to sign him. Gerry Hamstra, Zwolle's technical director, admitted there is slight interest in Kostons. Hamstra also said he expects something to happen this summer, but he did not mention any names. Incoming Hearts manager Wouter Vrancken will be aware of the player from his time in Belgium.