I could argue no sane club would expect a player who has handed in a transfer request, had multiple reports about conflicts with a manager, to turn up and it have no effect on performance, attitude or desire. What happens if he does stay and plays to his normal standard, and next season Barca don't come for him? Lets assume a standard Liverpool season of a top 6 finish, no trophy, what other teams are coming for him at a price Liverpool would accept? I can't see how he fits at Real, he won't be sold to a British club bar maybe City, so you now have a player who hasn't wanted to be there, has done his job and can't get a move he really wants.
What could go wrong?