Gnonto joined the Swiss club in 2020 but after scoring just a single goal in his debut season, impressed for them last time out.
Making 36 appearances in total, the attacker scored ten goals in addition to providing five assists, and helped his side become the Swiss champions.
His displays have seen him become admired by Leeds, who want to bring him in to expand their options in the final third and are in talks with Zurich.
Leeds have now reached a personal agreement with the Italy star himself for the transfer, according to Italian daily Gazzetta dello Sport.
However, an agreement has not been found with Zurich themselves and Leeds must agree a fee.
It remains to be seen how much Leeds will pay, with a fee of €4m to €5m mooted, though it has also been suggested that Zurich want something closer to €8m to €10m.
The Whites currently have an injury to star stinker Patrick Bamford to worry about and they are looking to take on another forward so that they are not left short up front.