According to TuttoUdinese (h/t Calciomercato), the offer is worth €20 million and would include a €30 million buy-back clause for the Bianconeri.
The Italian champions are not expected to add any more players to their squad this summer, with the focus for the remaining weeks on departures. Kean is almost certain to leave, as the teenager needs playing time to develop.
The 18-year-old academy product spent last season with Hellas Verona and likely would have returned for this campaign had the side not been relegated. He showed flashes of his amazing potential, most notably in the shock 4-1 win over Fiorentina―one of Juventus' biggest rivals:
During the summer, he impressed in the Under-19 European Championships, playing a key role in Italy's run to the final. In that final, he bagged two goals as a substitute.
For all of his talent, Kean is still a raw prospect, and he's not ready to contribute for the Bianconeri. Another spell away from the club seems all but certain, with Cristiano Ronaldo and Mario Mandzukic set to receive the bulk of the minutes at the striker position.
Italian football used to have co-ownership, a system Juventus made use of frequently. Since the system has been abandoned, the Old Lady has instead used deals with buy-back clauses for their youngsters, rather than sending them out on loan. The clause incentivises clubs to actually develop players, ensuring they end up making a profit.
Per ESPN FC's Ben Gladwell, Rolando Mandragora joined Udinese in such a deal in July, highlighting the great working relationship between the two clubs. He too cost €20 million, and it will cost the Old Lady €26 million to get him back.
Fellow striker Andrea Favilli also left for Genoa in a similar deal after an impressive pre-season, per Gianluca Di Marzio (h/t Football Italia). Expect the same for Kean before the end of summer.