I would do this trade:
Bargnani and Toronto's unprotected first this year for Al.
Basically Toronto is giving us the pick to take Bargnani. We give them Al to give them a low post presence and hope that their pick turns into a top 5 pick.
Bargnani is expensive, but not end of the world expensive. He becomes our fourth big (behind Millsap, Favors, and Kanter) and we have more than enough cap room. Also, he comes off the books the same year that Favors and Hayward come off the books.
I'd take that risk for a chance at a top 5 pick, almost guaranteed to be a top 10 pick. Especially when Bargnani doesn't really hurt our cap space at all, and he does have some talent that you might get a little out of as well.