It would appear that Hendrick was offered a new contract, but he decided to move on whether that was to further his career or for more money we will never know. He was a decent squad player and to some degree he did not get the credit he deserved from some of the fans but he has decided to leave so good luck to him for the future.
Our transfer dealing do seem to be a last minute affair every year, knowing that Bardsley, Hart, Hendrick and Lennon would be out of contract come the 30th June 2020 if we wanted to keep them contracts should have been offered and completed by the end of December 2019, then if it was obvious that a contract extension was not going to be reached the club could have possibly received a transfer fee in the January window for these players.
As for millions walking out of the door, as anything been said regarding Gibson, surely he must be on his way in the coming transfer window.