Just doing some quick math on capfriendly, Jets have 66M tied up in 14 players moving forward (9F, 4D, 1G)
(F) Wheeler, Connor, Scheifele, Laine, Ehlers, Perreault, Lowry, Copp, and Little (on IR, unsure if he returns I haven't read anything on his status in a while)
(D) Morrissey, Pionk, Dahlstrom, Poolman
(G) Hellebuyck
RFA's: Niku, Roslovic, Harkins, Appleton - None of these guys are going to command a big raise. There's a few others in the system that could possibly compete for a roster spot although I haven't kept up on our prospects this year, people have been saying good things about Samberg on the board.
Add Gretzky and Orr to that team and if Little doesn't return you're pretty close to the cap already. If Little retires, you'd then look towards dealing Perreault for picks to save cap space, and only after that would I look towards trading someone like Wheeler/Connor/Ehlers to address cap space and depth with Laine likely getting paid the following year one of the core would have to be dealt at some point.