I don't think the Rangers move him. Yes, he didn't have the best playoff performance, but he fractured his ankle earlier in the season, and came back to play through it. Unfortunately from a fans perspective you are only as good as your last game/last series.
He became the clear cut leader of the team that had a lot of vets but lacked leadership. He brought them together and they had a tremendous season winning the presidents trophy. Not too mention. This guy eats pucks. Was leading the league in blocked shots before the injury. Over a full season he would have finished 2nd. He also crushes people and is among the leagues most physical blueliners.
For the Rangers, Drury is all over building this model of a physical team, that is tough to play against. He moved out Goodrow because of a bad contract only. Now if he's moving out the teams most physical Dman, and a guy that plays the right side. How is he replacing that in Free Agency, or via trade?
Team would lose its Captain, best shot blocker, most physical defenseman. There's one player in the current top 6 that is difficult to play against. That's Trocheck. Lafreniere also plays physical, but not in the same sense as Trocheck. Kreider used to play a more physical game. I don't think you can label him that anymore. On D, Schneider is a watered down version on the physical side, but is progressing to be a better two way Dman. Miller, at 6'5 and among the strongest players in the league. He doesn't have a mean streak.
Lose #8, and the team becomes much easier to play against, and far less physical.