I worry that when articles start popping up in papers about Barca/Real/Bayern etc are going to buy player X it means that player X is wanting to move and his agent is putting it out there.
It was only after Gerrard retires that it was revealed that there had been enquires made for him (unsurprisingly I suppose) by many of the continents elite teams in the 08-11 period only to be rebuffed by the player himself. I don't recall any of this being reported or even speculated on in the sports media at the time.
No smoke without fire I fear.
Real and Barca don't require agents to let them know if a player wants a move. They usually simply use existing players, or their pet newspaper (Marca or whatever), to start mentioning their names, and start signalling their interest first. That usually draws out the agent and player.