To reply to the pair of you:
Phoenix had to pay Datsyuk's cap number dollar for dollar... meaning, of course, that his 7.5 mil cap hit was paired with a 7.5 mil salary.
The difference here is that Zetterberg's 6 mil cap hit each of the next three years is paired with a 3.35, 1 and 1 mil salary. So, yes, strictly speaking we're talking about relatively similar events but in terms of actual dollars at play we aren't talking about the same thing at all. A team looking to slip by the floor on the cheap can spend 5.35 million over three years and buy themselves 18 mil in cap space. In real terms they can save themselves over 12 million bucks by trading for Z.
All he has to do to secure the "value" here is not retire out from under the team that acquires him.
So, as I've not seen a situation like this crop up before, these being some of the first step down deals to age out, I was curious what a team might be willing to part with asset-wise to save real money.