The Vegas Golden Knights as always are going to be a very busy team this summer, and even though the cap is going up, the deadline additions of Tomas Hertl and Noah Hanifin and Hanifin's eight-year extension have them with a projected cap space of less than $1 million with key players like Jonathan Marchessault and Chandler Stephenson as pending unrestricted free agents.
Marchessault is an original Golden Knight going back to the trade from Florida to Vegas in 2017 and there is reportedly mutual interest in getting an extension done, but with cap room so tight, someone is going to have to be moved out.
With Hanifin extended, there are rumors and I'd put them at an e3 right now that the player who could be moved is Shea Theodore. The 28-year-old is a top pairing blueliner who has 40+ points each of the last five seasons, but he has a year remaining at $5.2 million AAV and it might be difficult to re-sign him after next season.
The return for Theodore with his reasonable salary could be massive, as defensemen of his quality are at a premium. GM Kelly McCrimmon needs to add some young talent with low cap hits, and that could be possible in deal for Theodore.