Sinckler last signed a contract (well one that's been made public) in October 2016 - could therefore quite possibly be out of contract at the end of the season. That said if he was leaving I would have though there would have been more noise about it.

Danny Care is also out of contract this summer but there hasn't been much in the press about him leaving since November.

I suspect that the club has already re-signed a lot of the senior players they intend to keep but for whatever reason have not chosen to make this public.