This might be a difficult one for Washington, but not as difficult when the Cancuks had Schneider and Luongo.
Holtby could fetch a massive long-term deal with another team if Washington doesn't sign him, Samsonov could be their goalie of the future. But also, Washington is better off trading one before the expansion draft so they don't lose or have to do a trade to ensure their roster is safe like Columbus, Florida, Pittsburgh did with Vegas.
This could go one of two ways.
1. Just trade Samsonov in a package deal for a star at the deadline, between 2020-22, to a rebuilding team in need of a young goalie bound to be a starter. For now we'll just say either Minnesota, LA or Ottawa.
2a. If nothing gets done with Holtby trade him to either Buffalo, Detroit or Edmonton (maybe a sign and trade or those teams wait for free agency, or the trade will consist of conditional picks).
2b. Trade Holtby to the highest bidder and that team will let him test the market. Say Calgary, maybe Colorado or even St. Louis.
I personally would keep Holtby if I was Washington considering he has done a ton for that franchise, don't want to sign him and let Samsonov sit on the bench when he's in his prime.
But if I do see Holtby ending up anywhere I would think it'd be likely Edmonton.