Loans

Can someone explain how loans work with regards to the financials? (I know I can google this, but I'm lazy and I enjoy the insight from all you fellow FulhamUSA-ers.) I assume that the team that receives the loanee pays the wages, but is there ever any other compensation negotiation? When a player is transferred, the teams have to agree on monetary terms and then the new team must negotiate a contract with the incoming player. But I don't think that I've ever heard about teams negotiating the details of a loan (though it must happen).

And specifically to Fulham, are we still paying Piazon's wages? Do we cover his treatment or did we send him back to Chelsea broken?