A very modest increase hockey on ice performance (maybe Domi over Holmberg0. this season at a astonishing high price.
Leafs can't afford Murphy for the next three full seasons.
Is there reason to think Vrana is going to good this season?

Detroit's not retaining 50% on Vrana for 1.5 years, For players we've no use for. Detroit passes.

CHI accepts.

Why not? We'd be getting two waiver exempt prospects and a 3rd (+ Engvall) for a player we no longer want on the team.

Okay so are we flipping Engval immediately then? because the whole reasoning of moving Vrana is to open up a spot for Robby Fabbri. Acquiring Pierre Engval kind of defeats that purpose.

Vrána wasn't waived to make room for Fabbri, that's a red herring. If Fabbri had been the cause of all this then there are a dozen other players that would have been waived ahead of Vrána, we're carrying three goalies for example.

Engvall or Erne or Hellberg/Nedeljkovic would be waived in this scenario and we would gain two waiver exempt prospects for a player we're losing for nothing anyway.

This scenario isn't realistic anyway because Yzerman will have tried to trade Vrána before making a decision to waive him. Only if Yzerman fails to find a trading partner for Vrána does he make this move.