BigKing
Blake Out of Hell III: Back in to Hell
If Tarasenko had much value, Seattle would have taken him and used him to trade now or at TDL. They easily could have retained too making it more enticing for a contender. StL will need to pony up in some way (retain or attaching a pick) to unload him this off-season.
Or they just prefer Dunn long term to whatever asset they'd get for Tarasenko.
I'm not entirely positive they will have to retain or even attach a pick: depends on the team trading for him. Kings have the cap space and the contract is only two seasons so they could simply take it but basically give STL nothing for him.