Interesting indeed. Not all that much for Flyers to give up, thought the salary is somewhat high. I think the Jets would match because they think could get more for Trouba in a trade,,,,when he's signed for five years.
Here's the factor, that just may nix the signing. If Trouba values his UFA status in two years, he doesn't sign the deal.

I don't know if you need to offer sheet him. He wanted out of WPG before and he's gonna want close to 8M. Jets don't have cap room for that.