Remember, the important thing is he gets first team games, if he's inconsistant(he is) and not dependable, you don't want to give him 6 months first team just to find out he's crap, but have his performances hurt the team. Put it this way, if he's not going to be playing, playing 1st team games at Juve is about 17000% more useful than playing in reserve games with crap players, with little competition with kids.
So its a better situation by far, even if you are paying his wages, at least the loan gives him a chance to become the player he might be, if he gets form back, he comes back and helps you next year, otherwise you'd still be paying him, but in a year he'll still be useless, also playing for Juve he might get interest enough to make an ok amount of money back if you sold him, rotting in the reserves you'd make a huge loss selling him next year. ITs better whichever way you look at it, unless you think he's brilliant right now and should be starting, I saw entirely no evidence of that last year. If you make money off it aswell, it just gets better. Remember Carson was considered a player who was back up and decent enough, and him going out on loan was changing the clubs plans somewhat. When a team takes a non working player whose destined for the bench, its not quite the same situation. I reckon theres likely to be no "fee" for the loan but they'll be paying some/all of his wages.
Funnily enough, it would appear, having been warned personally, publically to not go after Schwarzer, then Wenger, Mr " Barcelona have no respect, we told them he wasnt for sale and they still tried to get him" , turned around and yet again did exactly the same thing he was complaining about.
This is why I wasn't even slightly irked by Barca's "bad behaviour" because Arsenal and every single club in the world do the exact same things and Wengers done it on numerous occasions, which having known that made his "we won't even talk to them because they upset us so badly" crap that Wenger and his higher ups were spouting utterly ridiculous sounding in the first place.