The Argentine international is under contract with Udinese until 2024 and would cost Leeds at least £25m (€28m).
Negotiations are well underway between the clubs over a fee for De Paul and a deal could be done quickly.
It would be another impressive signing for Leeds were they to pull off a move for De Paul.
Reports in Italy suggest he wants to leave Udinese for a bigger challenge and Leeds could offer him an ambitious project.
De Paul scored seven goals and delivered six assists for Udinese in Serie A last season.