United want to secure Hernandez on a free transfer with the Uruguayan set to part company with Hull after four seasons at the KCOM Stadium.
Hernandez’s deal expires on June 30 and the forward has not accepted an extension with Hull, despite being offered what Tigers manager Nigel Adkins called “one hell of a contract”.
Hull are fighting to prevent a player who cost Â£10m in 2014 leaving for nothing but Hernandez is at the top of Leeds’ list of centre-forward targets and United have been drawing up an offer for the 27-year-old.
Hernandez missed most of this season with a ruptured Achilles tendon but still managed to amass eight goals, despite playing only 10 times.
He returned to full fitness in March and helped to keep Hull clear of relegation but he is likely to move on from City, a club he helped win promotion to the Premier League in 2016. Hernandez - originally signed from Palermo for a club-record fee - was close to a Â£20m move to Aston Villa that summer but failed to agree personal terms.
United want a proven, UK-based striker to lead their line next season and Hernandez is emerging as a leading option with the domestic transfer window now open.
Leeds have been heavily linked with Jerry Mbakogu, a striker with Carpi in Italy’s Serie B, and have a Â£3m option to sign him but Hernandez is seen as a more astute investment on account of his performances and experience in the Championship.
Adkins admitted before the end of the season that he was uncertain about Hernandez’s future, saying: “Is he going to be here or is he not? We’ve offered him one hell of a contract to be here but he’s not signed it at the moment. We’re just waiting to see what happens.
“He’s a talented player. I believe he was going to go to Aston Villa for Â£20m or something, then his representatives scuppered it because they wanted a bit more (in wages).
“A player who was the subject of a huge offer could leave the club for nothing this summer which is not great. But obviously he’s got his representatives, like all players, who have their jobs to do.”Leeds are putting an increased focus on the domestic market following much criticism of their foreign recruitment last summer.
Swansea City defender Kyle Bartley - on loan at Leeds for the 2016-17 season - remains another major target after United’s 13th-placed finish in the Championship.