Well, the Rangers boldly decided to go younger last year at the cost of a probably playoff berth. As the roster shakeup proceeds, who might become available to Seattle as a result?
(My basic criteria are here, and my suppositions are guided by data from capfriendly.com and hockeydb.com)
As a consequence of going young (with all the Entry-Level contracts that usually entails), there actually aren't that many Rangers on the roster now under contract for the 2020/2021 season:
Forwards: Mika Zibanejad
Defensemen/Defencemen: Brendan Smith, Kevin Shattenkirk, Marc Staal
Goalies: Henrik Lundqvist
So, I can't imagine Lundqvist leaving New York. Besides, he has a No Movement Clause. Shattenkirk and Staal do as well. So, barring any of them choosing to waive it, that leaves us with Zibanejad and Smith. The former carries a much higher cap hit ($5.35 million a year, exactly a million more than Smith), the latter had a modified No Trade Clause. Smith is four years older, which makes me lean in his direction, so let's go with that.
Brendan Smith (Right Defenseman/Defenceman)
Why New York Would Make Him Available: Well, not to put too fine a point on, he was recently made available to the entire NHL. If the Rangers can get rid of him before the forthcoming expansion draft I'm sure they will. That said, there are worse ideas than seeing if he rebounds (especially after trading away as much as they did for him) in the near term.
Why Seattle Would Want Him: While he wouldn't fetch as much as a trade chip again, defenders on the right side of any quality are in demand, so he could be useful in that regard. And if he's a bit rich at his current price point in New York, he'd be a great way to temporarily boost Seattle up to the cap floor.
Obviously, the best case scenario for Smith and Seattle would be for him to find his best game again and be a steady defensive presence. But even if he doesn't, both parties could benefit from Smith joining the organization. For however long that might be.