Quoting: dls9
It would be unusual, but that's why Arizona is getting more of a return.
I personally think the asking price on Chychrun is ridiculous. The team trading for that a star in those massive deals always never comes out on the winning end (Karlsson, Pacioretty, Eichel) ... and I think Leafs Management is smart enough to know that. Hockey is a variable game, and Chychrun has just as good a chance of coming to Toronto and being mediocre as he does becoming a top 2 star. We've seen it happen tons of times. I think a management group as smart as Toronto's realizes this, and if they're paying the full asking price, they're going to minimize risk by asking for some retention. It's not like AZ needs the cap space ...
I don't particularly think any of those trade references are applicable here. Patches trade worked out for vegas in the beginning, it went bad because they so completely mismanaged their cap that they had to pay to offload him, he was also on the verge of 30 when Vegas acquired him. The Sabers absolutely ran Eichel into the ground value wise by playing chicken with his surgery, and we haven't really gotten to see how that deal worked out yet (too small a sample size, give it another season to see how Eichel bounces back from the surgery and time off the ice). Karlsson was also on the door to 30, and had a massive injury history when traded, he was already a shell of the player he had been across his early to mid 20s.
Chychrun on the other had is in his mid 20s, while he does have some injury history, it seems less extensive than those listed above, and he has multiple years left on a team friendly deal, as opposed to an expiring contract or a 10mil aav. I don't think what Arizona is asking for is unreasonable given the circumstances, and they don't need to move him if teams don't want to pay, they loose onthing by keeping him around (as opposed to patches and Karlsson who would be gone/need resign, or Eichel who said he would not play for the team anymore)