Song, currently on loan from Barcelona, looks as if he will not be returning to the Boleyn Ground next term, and Donsah possess all the strength and technical abilities of the Cameroonian international.
Being Ghanaian, Donsah has been compared with Chelsea legend Michael Essien in the past, and at his young age he still has a long way to go in his development, despite having already impressed in Serie A.
Cagliari have been relegated from the top flight this term, and that looked as if the Hammers would win the race for his signature as he pushed a move away.
However, there have been no indications of a formal bid from the East London club, and the new report claims that Juve have agreed a €6 million fee for Donsah, and have reached an agreement in principal to sign him on a four-year contract.
It now looks as if the Hammers have lost out on their key summer transfer target, although they may be able to move for the young midfielder on loan for a season, with the report stating that the Serie A champions and Champions League finalists are keen to send him out for the next campaign to guarantee consistent playing time to aid his development.