There seems to be a lot of speculation about this among fans, and I even responded to some other trade thread about this potential deal. At first I thought that this would have to be a 3 or 4 team deal at least to make it work, but I'm not so sure. LA wouldn't want too much change if they're going to make a run at the title, and frankly don't have much else to offer in a trade. Anyway, here is my suggestion for how a straight-up deal would have to look, in my opinion.

LA gets: Bargs-Gray- Kleiza/Fields...most would assume Ed/Amir, but with Jordan Hill and Antawn Jamison, what LA will really need if they lose Gasol is more size, and that's Gray. This deal gives LA 3 things they need without them having to give up much. First, they get Bargs, and get a D'Antoni type lineup, with one real big (Dwight) and a bunch of perimeter players, except this time D'Antoni will actually have 2 bigs on D, and Bargs rebounding issues should be less problematic both because of Howard, and because of the system. Second, they get Gray, and they could use a dependable vet behind Howard because right now Sacre is the only other truly big body. Third, they get wing depth. D'Antoni likes Fields, as he praised him frequently him NY. But if the brass don't like his contract, I can see them settling for Kleiza, who as a 3/4, gives them another decent rebounder if they use unconventional lineups at times. In a straight-up deal, I don't know that any team can offer as decent a package and only really take back Gasol.

Toronto gets: Gasol. Period. Gives us a true post player who knows how to pass the ball, and can thus serve as an actual go to player in the post for us. It's definitely a risk with his sudden knee issues, but I'd still take him starting 1/2 or 2/3 of possible games than the way Bargs is playing now for every game. He would mesh well with our shooters by initiating our inside-outside game, be able to hit JV, Ed and Amir with cuts in the paint, and actually rebound like a big man, which would give us 4 good rebounding bigs for the first time ever!!!

Potential issues:
-cap space....no team is really better off after this deal, but also neither team's flexibility is destroyed. If LA demands cap relief, we can't offer it. This is the most likely reason for a 3rd team to get involved, as LA also doesn't have a lot of assets. They can't offer money either, won't have high picks, and they wouldn't get much return for their other players.
-draft picks.....the main reason I think a straight up deal is possible. TO won't demand one, even if they might want to replace the one they may lose to Houston. Can't see it being a dealbreaker for LA either, since they're still poised to contend for the next couple of seasons, so youngsters won't get much playing time.
-roster space.....strictly speaking, the deal doesn't work straight up. LA would either need to waive a couple of players or send them to us, which in turn might alter the deal a bit if we have to throw in another player. Pretty much any 2 of Clark, Ebanks, Morris, Johnson-Odom and Sacre. I'm indifferent as I don't think any of these players will find more success or opportunity in Toronto. This should only alter details of the trade though.

For what it's worth:
The deal of Bargs-Gray- Fields or Kleiza straight up for Gasol, works on ESPN trade machine. Hard to tell beyond that because a lot of the spare parts LA might waive or throw in won't be available til Dec 15, so trade machine doesn't let you use them(and LA's roster doesn't have similar contracts). Again though, if it's just down to spare parts, it should not affect whether the deal goes through.