Adrien Rabiot's name is called with Manchester United once again in the recent times. His current contract is about to expire by the end of June so there is a big opportunity for the Red Devils to finish the deal by no transfer fee. It is up to whether Rabiot would like to join their side also of course. Because if I don't remember wrong he wasn't very willing to join them before also.
Back then Manchester United got really close to finalizing the agreement but it didn't happen. After a while Rabiot must have made a statement like he was contented with not joining them because of their poor performance.
But this season has been really well for the Red Devils so maybe they can be more convincing this time. Rabiot is a skilled midfielder he can really be useful.
Depend on Manchester United standings position for signing Rabiot, maybe if failed with top fourth standing or Manchester United not participants in Champion League I don't sure Rabiot will move to United because many teams interested with him exactly become free agent and teams not have to pay transfer values.
I expect Rabiot to get a lot of offers as there will be no transfer fee. Maybe Newcastle United might want to sign him. I think they will try to build an ambitious squad as they will play in the Champions league next year. Whichever team Rabiot chooses will go to him. If Juventus offer a new contract, maybe they can consider staying with the team.