If Marleau retired and Arizona didn't have to pay Marleau any actual money and only take his retired cap hit then it would make far more sense to them. Trading for him and then buying him out so the Leafs can re-sign him for cheaper isn't very appealing to Arizona at all.
Agreed, doesn't make fiscal sense for AZ to do that. They count every penny.
Seems like a lot of posters don't know about the buyout period being in June and signing bonuses generally paid on July 1, which is the beginning of a new NHL fiscal season. There's a second buyout window, but that involves the team having arbitration cases as well as that player having to be on the roster by a certain point in time to be a candidate for a buyout.
Honestly, for Marleau to still play next season and the Leafs to get him off their books, they are going to have to find a 3 way type deal. Send him to AZ for them to retain a portion is his $1.25 million salary, then have AZ send him off to a team he wants to be one. It's the Brassard trade between Pitt/Ott/LV last season. If the Leafs retained 20% which is $1.25 million cap, that leaves AZ with $5 million, then if they retained, it's $2.5 million to the final team in terms of cap ($500K in real money).
First part of the transactions wouldn't be too difficult to do, it's the second part which is completely dependent on the couple of teams that Marleau would ok going to actually wanting him for the cap that he would cost them. Does it make sense for them? Who knows.