Leafs probablyncan't afford the the 5m cap hit of Nisko, which is one reason Gardiner isn't returning. For the same reason you "have" to trade him...for cap reasons, the Leafs couldn't accept him without sending money back in a trade.

There's pretty likely a team out West that outbids those picks for Niskanen next summer if he no longer fits into the Caps' plans, but I would be surprised if the move is necessitated by the signing of Jan Rutta, rather than the development of Lucas Johansen.

I know Rutta was better than Kempny in Chicago last season, but Kempny really stepped up a bit for the playoffs, and also benefitted a bit from developing some chemistry with Carlson and Eller at their best.

Could probably keep Niskanen and get at 22 person roster under that cap, or the cap might go up more. Could sign Emelin now, for two years, for less than Rutta, and be more sure you end up with someone experienced who can kill penalties if you have to trade Niskanen, but you have to get Emelin at a price where you're comfortable waiving him and paying him in the AHL if the right trade for Niskanen isn't there. Better to take it a year at a time.